This document summarizes model experiments conducted to investigate hydrodynamic nonlinearities in jack-up platforms. Two simplified jack-up platform models were tested in regular and irregular waves. Force, acceleration, and displacement data were collected. Preliminary results showed the influence of structural response on hydrodynamic loads was significant near the platform's resonant frequency. Nonlinear effects like quadratic drag were observed. Paired regular wave tests provided an initial check of superposition principles. Overall, the experiments aimed to better understand jack-up platform hydrodynamics to inform computer simulations and design criteria.
OMAE2014 - 23661 Experimental Assessment of The Behaviour Of A Pipe Vibration...Luan Tochetto
The document describes experiments conducted to assess the behavior of a Pounding Tuned Mass Damper (PTMD) installed on a pipe underwater. A small-scale test apparatus was constructed to model a submarine pipe section. Free and forced oscillation tests were performed on the pipe both with and without a PTMD installed, in air and underwater conditions. The results showed that underwater, the natural frequency decreased due to added water mass, while damping increased due to fluid viscosity. With the PTMD installed, two natural frequencies were observed corresponding to the two-degree-of-freedom system. The PTMD was found to reduce pipe vibration amplitudes both in air and underwater through energy dissipation, though its performance was affected by surrounding fluid
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses ionospheric effects in SAR interferometry and methods for estimating the ionosphere's impact. It presents two main methods: the split spectrum method, which uses interferometric phase from lower and upper subbands, and the range group-phase delay method, which takes the difference between phase delay and group delay estimates. Theoretical analysis and experiments with ALOS-PALSAR data show that both methods can reliably estimate ionospheric phase screens given sufficient coherence, though the range group method has better statistical performance. Accounting for ionospheric effects will be important for precision InSAR at P-band and L-band and even higher frequencies.
This document provides an overview of earthquake resistant design for nuclear power plants. It discusses generating design basis ground motions, safety classification and seismic categorization of systems, seismic qualification by analysis and testing, issues with hard rock and soil sites, and concludes that structures, systems and components must be qualified for two levels of earthquakes through analysis, testing or a combination.
This document discusses the development of an innovative logging while drilling (LWD) system using underground georadar (UGR) technology. It aims to improve navigation and maximize oil recovery from directional drilling. Key challenges include developing compact antenna designs that can operate in harsh downhole conditions and suppress leakage between antennas. The proposed system uses stepped frequency continuous wave radar with two receiving antennas to differentiate between leakage and boundary reflections. A prototype has been developed with antennas placed inside stabilizer blades to displace drilling fluid and achieve over 45dB leakage suppression without an antenna spacing. The design provides stable characteristics and anisotropic signals that can detect boundaries within 1-5m and estimate properties like propagation velocity.
Engineering geophysical study of unconsolidated top soil using shallow seismi...Alexander Decker
1) An integrated geophysical study using seismic refraction and electrical resistivity techniques was conducted to image the shallow subsurface at the University of Peshawar, Pakistan.
2) Analysis of seismic refraction data along profile AB revealed a two-layer subsurface structure, with a top layer of loose soil 0-4 meters thick having P-wave velocities of 223m/sec underlain by a layer with a velocity of 316 m/sec.
3) Electrical resistivity surveys along two profiles validated the two-layer model, detecting a top soil layer 1.1-1.3 meters thick with resistivities of 38-52 ohm-meters underlain by a more conductive clay-rich layer with resist
The document summarizes experiments conducted to study the effect of dissipation blocks on the energy downstream of compound weirs. 240 experimental runs were performed using different types of triangular, horizontally, and vertically cut dissipation blocks placed in the stilling basin. Measurements of relative energy dissipation, hydraulic jump length, and roller length were taken for each experimental configuration. The results showed that compound weirs with lower V-notches and all dissipation block types had high energy dissipation efficiency, especially at high discharges. Hydraulic characteristic values were better for triangular cut angles of 45° and 60° compared to other block configurations. In conclusion, dissipation blocks improved hydraulic performance by increasing energy dissipation and reducing hydraulic jump length.
1) The study investigates the effect of reservoir hydrostatic pressure on the seismic response of roller compacted concrete (RCC) dams using finite element analysis.
2) Analysis of the Kinta RCC dam in Malaysia shows that hydrostatic pressure increases stresses by 25% and changes displacement response from negative to positive direction. It also causes more damage at the heel of the dam.
3) Consideration of hydrostatic pressure leads to a 13% increase in maximum horizontal deformation, from 76.5 mm to 86.6 mm, and changes the zone of peak deformation from the base to the crest of the dam. It also changes the displacement response of nodes from negative to positive.
OMAE2014 - 23661 Experimental Assessment of The Behaviour Of A Pipe Vibration...Luan Tochetto
The document describes experiments conducted to assess the behavior of a Pounding Tuned Mass Damper (PTMD) installed on a pipe underwater. A small-scale test apparatus was constructed to model a submarine pipe section. Free and forced oscillation tests were performed on the pipe both with and without a PTMD installed, in air and underwater conditions. The results showed that underwater, the natural frequency decreased due to added water mass, while damping increased due to fluid viscosity. With the PTMD installed, two natural frequencies were observed corresponding to the two-degree-of-freedom system. The PTMD was found to reduce pipe vibration amplitudes both in air and underwater through energy dissipation, though its performance was affected by surrounding fluid
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses ionospheric effects in SAR interferometry and methods for estimating the ionosphere's impact. It presents two main methods: the split spectrum method, which uses interferometric phase from lower and upper subbands, and the range group-phase delay method, which takes the difference between phase delay and group delay estimates. Theoretical analysis and experiments with ALOS-PALSAR data show that both methods can reliably estimate ionospheric phase screens given sufficient coherence, though the range group method has better statistical performance. Accounting for ionospheric effects will be important for precision InSAR at P-band and L-band and even higher frequencies.
This document provides an overview of earthquake resistant design for nuclear power plants. It discusses generating design basis ground motions, safety classification and seismic categorization of systems, seismic qualification by analysis and testing, issues with hard rock and soil sites, and concludes that structures, systems and components must be qualified for two levels of earthquakes through analysis, testing or a combination.
This document discusses the development of an innovative logging while drilling (LWD) system using underground georadar (UGR) technology. It aims to improve navigation and maximize oil recovery from directional drilling. Key challenges include developing compact antenna designs that can operate in harsh downhole conditions and suppress leakage between antennas. The proposed system uses stepped frequency continuous wave radar with two receiving antennas to differentiate between leakage and boundary reflections. A prototype has been developed with antennas placed inside stabilizer blades to displace drilling fluid and achieve over 45dB leakage suppression without an antenna spacing. The design provides stable characteristics and anisotropic signals that can detect boundaries within 1-5m and estimate properties like propagation velocity.
Engineering geophysical study of unconsolidated top soil using shallow seismi...Alexander Decker
1) An integrated geophysical study using seismic refraction and electrical resistivity techniques was conducted to image the shallow subsurface at the University of Peshawar, Pakistan.
2) Analysis of seismic refraction data along profile AB revealed a two-layer subsurface structure, with a top layer of loose soil 0-4 meters thick having P-wave velocities of 223m/sec underlain by a layer with a velocity of 316 m/sec.
3) Electrical resistivity surveys along two profiles validated the two-layer model, detecting a top soil layer 1.1-1.3 meters thick with resistivities of 38-52 ohm-meters underlain by a more conductive clay-rich layer with resist
The document summarizes experiments conducted to study the effect of dissipation blocks on the energy downstream of compound weirs. 240 experimental runs were performed using different types of triangular, horizontally, and vertically cut dissipation blocks placed in the stilling basin. Measurements of relative energy dissipation, hydraulic jump length, and roller length were taken for each experimental configuration. The results showed that compound weirs with lower V-notches and all dissipation block types had high energy dissipation efficiency, especially at high discharges. Hydraulic characteristic values were better for triangular cut angles of 45° and 60° compared to other block configurations. In conclusion, dissipation blocks improved hydraulic performance by increasing energy dissipation and reducing hydraulic jump length.
1) The study investigates the effect of reservoir hydrostatic pressure on the seismic response of roller compacted concrete (RCC) dams using finite element analysis.
2) Analysis of the Kinta RCC dam in Malaysia shows that hydrostatic pressure increases stresses by 25% and changes displacement response from negative to positive direction. It also causes more damage at the heel of the dam.
3) Consideration of hydrostatic pressure leads to a 13% increase in maximum horizontal deformation, from 76.5 mm to 86.6 mm, and changes the zone of peak deformation from the base to the crest of the dam. It also changes the displacement response of nodes from negative to positive.
1) This document summarizes a student's study on optimizing the shape and dimensions of a point absorber wave energy converter to improve power extraction.
2) The study evaluated three shapes - a cylinder, cylinder with hemispherical bottom (bullet), and cylinder with conical bottom (cone) - and determined the bullet shape with a 10m radius and 15m total vertical length was most efficient.
3) Accounting for viscous effects through computational fluid dynamics simulations reduced predicted power extraction by over 10% and shifted the optimal damper configuration for certain sea states.
This document summarizes an experiment that measured wave forces on different shapes of wind turbine towers, including a cylinder, square rod, and actual tower model. Models were tested in a water tunnel using particle image velocimetry (PIV) to analyze velocity profiles and calculate drag forces via two methods: applying momentum conservation to a control volume around each model, and determining drag coefficients based on Reynolds number and model geometry. Four layers within the control volume were analyzed separately to obtain velocity measurements at different depths.
Abstract: Geo-technical engineering as a subject has developed considerably in the past four decades. There
has been remarkable development in the fields of design, research and construction of dam. India is capable of
designing and constructing a dam that would withstand a seismic jolt. The country needs water and electricity
to provide its people good living standards. Hydropower is the solution to the country's requirements, and this
can be achieved by storing water in dams.
In the past, earthquake effects may have been treated too lightly in dam design. Are such dams safe,
and how have they fared in previous earthquakes, this Paper will be limited to the some of finding about one
concrete types.
What will happen to dams during severe earthquake shaking? It is obvious that at present engineers
cannot answer this question with any certainty. But we are very much aware of the threat of disastrous losses of
life and damage to property if dams should fail, and we are making great effort to increase our under standing
of this complex topic.
This Paper deals with the case study of totaladoh Dam Situated in Vidarbha Region of Maharashtra
for Seismic Analysis by I.S.Code method (Simple Beam Analysis method). This also includes future scope of
analyzing the same dam for Seismic safety by very accurate method i.e. finite element method.
Keywords: Earthquake, The finite element method, Indian Standard codes(I.S.Code), horizontal
seismic coefficient (αh ),Hydrostatic pressure, Seismic analysis,
1. The document discusses wind tunnels, which are devices used to study aerodynamic forces on models in controlled airflow conditions.
2. It describes various types of wind tunnels classified by speed (low speed vs high speed) and operation mode. Low speed wind tunnels aim to reduce turbulence using screens, honeycombs, and contractions prior to the test section.
3. Key components like the diffuser are explained, which recovers kinetic energy as pressure. The document emphasizes the importance of dynamic similarity between models and full-scale objects through non-dimensional parameters like Reynolds and Mach numbers.
The Hydrodynamic Performance Examination of a New Floating Breakwater Configu...IJAEMSJORNAL
It is critical to protect coastal and offshore structures. Most current studies and scientific investigations are centered on how to protect seashore with an efficient and cost-effective system. This study involved the testing of a new floating breakwater configuration (FB). A series of experiments were carried out in the lab of The Higher Institute of Engineering (El-shorouk City) on the new model and the traditional vertical plane FB without a curved face to compare their behaviours and performance in wave attenuation. The incident, reflected, and transmitted wave heights were measured, and the coefficients of reflection, transmission, and energy dissipation were calculated using these measurements. In terms of hydrodynamic performance, the curved-face floating breakwater outperformed the traditional vertical floating breakwater, according to the study's highlights. The curved face model significantly reduced wave transmission values when compared to the traditional vertical configuration. The greater the concavity of the curve, the better the model handles waves, especially when the wave steepness is low.
Using Half Pipes as Permeable BreakwaterIRJET Journal
This document describes a study that investigated using half pipes as permeable breakwaters to protect coastlines in Egypt. Two types of half pipe breakwaters were tested experimentally and numerically: horizontal half pipes shaped like an H, and vertical half pipes shaped like a C. Physical models were used to identify the hydraulic performance of the barriers under different wave conditions. A numerical model was also developed using FLOW-3D software and validated against the laboratory data. The results showed that increasing the relative water depth decreases the amount of wave transmission through the barrier and increases wave reflection. Permeable breakwaters were found to effectively dissipate wave energy while avoiding issues caused by traditional solid breakwater structures.
The International Journal of Mechanical Engineering Research and Technology is an international online journal in English published Quarterly offers a speed publication schedule with the whilst maintaining rigorous proper review and the use of recommended electronic formats for an article delivery of expedites the process of All submitted research articles are subjected to immediate quick screening by the editors consultation with the Editorial Board or others working in the field as appropriate to ensure that they are alike to be the level of interest and importance of appropriate for the journal.
This document describes a numerical simulation of the dynamics of a tethered buoy system. It proposes a novel mixed finite element formulation to model the elastic cable in a robust way, even when the Young's modulus is very large. It also uses quaternion variables to describe the floating body's dynamics, providing numerical stability during large rotations. The coupled nonlinear equations governing the cable and body are discretized in time using the implicit Backward Euler method and linearized with a damped Newton's method. Validation simulations are presented to demonstrate the accuracy and robustness of the overall numerical procedure.
Development of Seakeeping Test and Data Processing Systemijceronline
This document describes the development of a seakeeping test and data processing system. The system includes two main procedures: wave generation and data processing. In wave generation, a linear filtering method is used to generate irregular waves that meet a target spectrum. In data processing, time domain and frequency domain methods are used to analyze experimental data on irregular waves, ship motions, and hull stresses. The system was tested using experiments on a ship model in irregular waves and showed accurate simulation and reliable data processing.
1) Researchers built a 1:13 scale model of a tidal turbine deployment platform and bridge pier to experimentally validate design loads for the full-scale structure.
2) The scale model was tested in a tow tank under expected tidal currents and wave conditions, and mooring forces were measured with load cells.
3) Preliminary single-point towing tests validated that the scale model was properly Froude-scaled, with a 99% coefficient of determination between experimental and theoretical drag forces.
This study examines tsunami forces on bridge decks through large-scale laboratory experiments and numerical simulations. A 1:5 scale concrete bridge deck model was installed in a wave flume and subjected to solitary waves of varying heights and clearances between the water and deck. Wave force time histories were recorded and decomposed into quasi-static and slamming components. Numerical simulations matching the experimental conditions showed good agreement with measurements. Both quasi-static and slamming forces increased significantly with wave height and clearance in horizontal and vertical directions. The results provide guidance for estimating tsunami forces on bridges.
This document summarizes a numerical study on free-surface flow conducted using a computational fluid dynamics (CFD) solver. The study examines the wave profile generated by a submerged hydrofoil through several test cases varying parameters like the turbulence model, grid resolution, and hydrofoil depth. The document provides background on the governing equations solved by the CFD solver and the interface capturing technique used to model the free surface. Five test cases are described that investigate grid convergence, the impact of laminar vs turbulent models, the relationship between hydrofoil depth and wave height, and the effect of discretization schemes.
Enumeration and validation of hydrodynamic characteristics over plane and seIAEME Publication
This document summarizes a numerical study that simulated wave generation, propagation, and run-up over plane and serrated slopes with varying angles and wave heights. The study used the FUNWAVE model to simulate waves generated by a piston wavemaker and calculate dimensionless parameters like maximum run-up and reflection coefficient. Results found run-up was higher for a 30-degree slope and lower for a 45-degree slope. Slopes with serrations reduced run-up and reflection coefficient by around 30% and 20% respectively compared to plane slopes. The bed friction coefficient for serrated slopes was quantified using a Navier-Stokes solver.
Lyapichev. Problems in numerical analysis of CFRDs (ICOLD Bull.155)6 p.)Yury Lyapichev
The document discusses several challenges and developments in numerically analyzing concrete faced rockfill dams (CFRDs). It notes that until recently, CFRDs were designed based on experience rather than analysis. Accurate models have since shown issues like excessive compressibility of downstream rockfill adversely impacting the concrete face. The document also discusses modeling earthquakes, the need for structure-specific models in some cases, and ensuring nonlinear analysis convergence. Overall, it emphasizes the importance of numerical analysis as a tool to supplement—not replace—engineering judgment, especially for extrapolating lessons from incidents at high CFRDs.
The document presents a theoretical and experimental analysis of a storm wave recorded by a pressure sensor. Linear wave theory, Stokes second-order wave theory, stream function wave theory, and cnoidal wave theory were used to estimate wave parameters like water depth, wave height, and wavelength. Experiments were conducted in a wave flume to model the storm wave and examine the effects of adding vertical cylinders in the wave's path. The placement of a floating wind turbine was also analyzed to minimize wave height effects.
Implementation of Wilcox k − ω model to UCNS3DArpit Aggarwal
Arpit Aggarwal implemented the Wilcox k-ω turbulence model in the UCNS3D computational fluid dynamics solver. Validation cases for the RAE-2822 airfoil and flow over a backward-facing step showed good agreement with experimental data and other models. The implementation allows for improved accuracy in complex geometries handled by the UCNS3D solver.
IRJET- Analysis of CR TOWER G+6 Buildings Having Top Rectangular Water Ta...IRJET Journal
This document analyzes the use of a tuned liquid damper (TLD) in a G+6 building with a top rectangular water tank in Ambikapur, Chhattisgarh, India to control vibrations. The building is analyzed under various dynamic loads. A TLD uses liquid sloshing to dampen structural oscillations. Analysis shows the TLD can effectively reduce responses to half of original values. Properly designed TLDs with optimal tuning ratio, depth ratio, and mass ratio are effective at reducing structural response to earthquakes and winds. The top water tank in this building acts as a TLD. Nonlinear models are used to analyze the liquid-structure interaction.
Large Eddy Simulation of Turbulence Modeling for wind Flow past Wall Mounted ...IJERA Editor
This paper will present the large eddy simulation of turbulence modeling for wind flow over a wall mounted 3D cubical model. The LES Smagorinsky scheme is employed for the numerical simulation. The domain for this study is of the size of 60 cm x 30 cm x 30 cm. The 3D cube model is taken of the size of 6 cm x 6 cm x 4 cm. The Reynolds number for the flow in respect of the height of the cube i.e, 4 cm is 5.3x104. The hexahedral grids are used for the meshing of the flow domain. The results are discussed in terms of various parameters such as velocity profile around the cube and the computational domain, the pressure distribution over the cube, near wall velocity profile and the shear stress distribution and also the result of drag coefficient is verified by neural network time series analysis using MATLAB. In this present study we have used the OpenFoam platform for the computational and numerical analysis. The numerical scheme employed is the combination of the steady state incompressible Newtonian flow model using SIMPLE algorithm followed by the transient model of incompressible Newtonian flow using PISO algorithm. We have observed that there is a constant positive drag coefficient in case of steady state simulation where as there is a negative lift coefficient in the initial run and a very low lift coefficient at the end of the steady state simulation.
Applications of Differential Equations in Petroleum EngineeringRaboon Redar
In modern science and engineering, differential equations are very important. Nearly all known physics and chemistry laws are indeed differential equations. Engineers, in order to investigate systems behavior, it is virtually necessary that they are able to model and solve physical problems with mathematical equations.
The document describes a study that investigated the depth-wise profiles of velocity and turbulence parameters in the proximity of a mid-channel bar using experimental and computational fluid dynamics (CFD) modeling methods. Velocity measurements were taken at various depths and locations near the mid-channel bar using an acoustic Doppler velocimeter (ADV). The study found changes in the velocity and turbulence profiles due to interactions between the fluid flow and the mid-channel bar. CFD modeling with the Reynolds stress model was also used to validate the experimental results.
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
1) This document summarizes a student's study on optimizing the shape and dimensions of a point absorber wave energy converter to improve power extraction.
2) The study evaluated three shapes - a cylinder, cylinder with hemispherical bottom (bullet), and cylinder with conical bottom (cone) - and determined the bullet shape with a 10m radius and 15m total vertical length was most efficient.
3) Accounting for viscous effects through computational fluid dynamics simulations reduced predicted power extraction by over 10% and shifted the optimal damper configuration for certain sea states.
This document summarizes an experiment that measured wave forces on different shapes of wind turbine towers, including a cylinder, square rod, and actual tower model. Models were tested in a water tunnel using particle image velocimetry (PIV) to analyze velocity profiles and calculate drag forces via two methods: applying momentum conservation to a control volume around each model, and determining drag coefficients based on Reynolds number and model geometry. Four layers within the control volume were analyzed separately to obtain velocity measurements at different depths.
Abstract: Geo-technical engineering as a subject has developed considerably in the past four decades. There
has been remarkable development in the fields of design, research and construction of dam. India is capable of
designing and constructing a dam that would withstand a seismic jolt. The country needs water and electricity
to provide its people good living standards. Hydropower is the solution to the country's requirements, and this
can be achieved by storing water in dams.
In the past, earthquake effects may have been treated too lightly in dam design. Are such dams safe,
and how have they fared in previous earthquakes, this Paper will be limited to the some of finding about one
concrete types.
What will happen to dams during severe earthquake shaking? It is obvious that at present engineers
cannot answer this question with any certainty. But we are very much aware of the threat of disastrous losses of
life and damage to property if dams should fail, and we are making great effort to increase our under standing
of this complex topic.
This Paper deals with the case study of totaladoh Dam Situated in Vidarbha Region of Maharashtra
for Seismic Analysis by I.S.Code method (Simple Beam Analysis method). This also includes future scope of
analyzing the same dam for Seismic safety by very accurate method i.e. finite element method.
Keywords: Earthquake, The finite element method, Indian Standard codes(I.S.Code), horizontal
seismic coefficient (αh ),Hydrostatic pressure, Seismic analysis,
1. The document discusses wind tunnels, which are devices used to study aerodynamic forces on models in controlled airflow conditions.
2. It describes various types of wind tunnels classified by speed (low speed vs high speed) and operation mode. Low speed wind tunnels aim to reduce turbulence using screens, honeycombs, and contractions prior to the test section.
3. Key components like the diffuser are explained, which recovers kinetic energy as pressure. The document emphasizes the importance of dynamic similarity between models and full-scale objects through non-dimensional parameters like Reynolds and Mach numbers.
The Hydrodynamic Performance Examination of a New Floating Breakwater Configu...IJAEMSJORNAL
It is critical to protect coastal and offshore structures. Most current studies and scientific investigations are centered on how to protect seashore with an efficient and cost-effective system. This study involved the testing of a new floating breakwater configuration (FB). A series of experiments were carried out in the lab of The Higher Institute of Engineering (El-shorouk City) on the new model and the traditional vertical plane FB without a curved face to compare their behaviours and performance in wave attenuation. The incident, reflected, and transmitted wave heights were measured, and the coefficients of reflection, transmission, and energy dissipation were calculated using these measurements. In terms of hydrodynamic performance, the curved-face floating breakwater outperformed the traditional vertical floating breakwater, according to the study's highlights. The curved face model significantly reduced wave transmission values when compared to the traditional vertical configuration. The greater the concavity of the curve, the better the model handles waves, especially when the wave steepness is low.
Using Half Pipes as Permeable BreakwaterIRJET Journal
This document describes a study that investigated using half pipes as permeable breakwaters to protect coastlines in Egypt. Two types of half pipe breakwaters were tested experimentally and numerically: horizontal half pipes shaped like an H, and vertical half pipes shaped like a C. Physical models were used to identify the hydraulic performance of the barriers under different wave conditions. A numerical model was also developed using FLOW-3D software and validated against the laboratory data. The results showed that increasing the relative water depth decreases the amount of wave transmission through the barrier and increases wave reflection. Permeable breakwaters were found to effectively dissipate wave energy while avoiding issues caused by traditional solid breakwater structures.
The International Journal of Mechanical Engineering Research and Technology is an international online journal in English published Quarterly offers a speed publication schedule with the whilst maintaining rigorous proper review and the use of recommended electronic formats for an article delivery of expedites the process of All submitted research articles are subjected to immediate quick screening by the editors consultation with the Editorial Board or others working in the field as appropriate to ensure that they are alike to be the level of interest and importance of appropriate for the journal.
This document describes a numerical simulation of the dynamics of a tethered buoy system. It proposes a novel mixed finite element formulation to model the elastic cable in a robust way, even when the Young's modulus is very large. It also uses quaternion variables to describe the floating body's dynamics, providing numerical stability during large rotations. The coupled nonlinear equations governing the cable and body are discretized in time using the implicit Backward Euler method and linearized with a damped Newton's method. Validation simulations are presented to demonstrate the accuracy and robustness of the overall numerical procedure.
Development of Seakeeping Test and Data Processing Systemijceronline
This document describes the development of a seakeeping test and data processing system. The system includes two main procedures: wave generation and data processing. In wave generation, a linear filtering method is used to generate irregular waves that meet a target spectrum. In data processing, time domain and frequency domain methods are used to analyze experimental data on irregular waves, ship motions, and hull stresses. The system was tested using experiments on a ship model in irregular waves and showed accurate simulation and reliable data processing.
1) Researchers built a 1:13 scale model of a tidal turbine deployment platform and bridge pier to experimentally validate design loads for the full-scale structure.
2) The scale model was tested in a tow tank under expected tidal currents and wave conditions, and mooring forces were measured with load cells.
3) Preliminary single-point towing tests validated that the scale model was properly Froude-scaled, with a 99% coefficient of determination between experimental and theoretical drag forces.
This study examines tsunami forces on bridge decks through large-scale laboratory experiments and numerical simulations. A 1:5 scale concrete bridge deck model was installed in a wave flume and subjected to solitary waves of varying heights and clearances between the water and deck. Wave force time histories were recorded and decomposed into quasi-static and slamming components. Numerical simulations matching the experimental conditions showed good agreement with measurements. Both quasi-static and slamming forces increased significantly with wave height and clearance in horizontal and vertical directions. The results provide guidance for estimating tsunami forces on bridges.
This document summarizes a numerical study on free-surface flow conducted using a computational fluid dynamics (CFD) solver. The study examines the wave profile generated by a submerged hydrofoil through several test cases varying parameters like the turbulence model, grid resolution, and hydrofoil depth. The document provides background on the governing equations solved by the CFD solver and the interface capturing technique used to model the free surface. Five test cases are described that investigate grid convergence, the impact of laminar vs turbulent models, the relationship between hydrofoil depth and wave height, and the effect of discretization schemes.
Enumeration and validation of hydrodynamic characteristics over plane and seIAEME Publication
This document summarizes a numerical study that simulated wave generation, propagation, and run-up over plane and serrated slopes with varying angles and wave heights. The study used the FUNWAVE model to simulate waves generated by a piston wavemaker and calculate dimensionless parameters like maximum run-up and reflection coefficient. Results found run-up was higher for a 30-degree slope and lower for a 45-degree slope. Slopes with serrations reduced run-up and reflection coefficient by around 30% and 20% respectively compared to plane slopes. The bed friction coefficient for serrated slopes was quantified using a Navier-Stokes solver.
Lyapichev. Problems in numerical analysis of CFRDs (ICOLD Bull.155)6 p.)Yury Lyapichev
The document discusses several challenges and developments in numerically analyzing concrete faced rockfill dams (CFRDs). It notes that until recently, CFRDs were designed based on experience rather than analysis. Accurate models have since shown issues like excessive compressibility of downstream rockfill adversely impacting the concrete face. The document also discusses modeling earthquakes, the need for structure-specific models in some cases, and ensuring nonlinear analysis convergence. Overall, it emphasizes the importance of numerical analysis as a tool to supplement—not replace—engineering judgment, especially for extrapolating lessons from incidents at high CFRDs.
The document presents a theoretical and experimental analysis of a storm wave recorded by a pressure sensor. Linear wave theory, Stokes second-order wave theory, stream function wave theory, and cnoidal wave theory were used to estimate wave parameters like water depth, wave height, and wavelength. Experiments were conducted in a wave flume to model the storm wave and examine the effects of adding vertical cylinders in the wave's path. The placement of a floating wind turbine was also analyzed to minimize wave height effects.
Implementation of Wilcox k − ω model to UCNS3DArpit Aggarwal
Arpit Aggarwal implemented the Wilcox k-ω turbulence model in the UCNS3D computational fluid dynamics solver. Validation cases for the RAE-2822 airfoil and flow over a backward-facing step showed good agreement with experimental data and other models. The implementation allows for improved accuracy in complex geometries handled by the UCNS3D solver.
IRJET- Analysis of CR TOWER G+6 Buildings Having Top Rectangular Water Ta...IRJET Journal
This document analyzes the use of a tuned liquid damper (TLD) in a G+6 building with a top rectangular water tank in Ambikapur, Chhattisgarh, India to control vibrations. The building is analyzed under various dynamic loads. A TLD uses liquid sloshing to dampen structural oscillations. Analysis shows the TLD can effectively reduce responses to half of original values. Properly designed TLDs with optimal tuning ratio, depth ratio, and mass ratio are effective at reducing structural response to earthquakes and winds. The top water tank in this building acts as a TLD. Nonlinear models are used to analyze the liquid-structure interaction.
Large Eddy Simulation of Turbulence Modeling for wind Flow past Wall Mounted ...IJERA Editor
This paper will present the large eddy simulation of turbulence modeling for wind flow over a wall mounted 3D cubical model. The LES Smagorinsky scheme is employed for the numerical simulation. The domain for this study is of the size of 60 cm x 30 cm x 30 cm. The 3D cube model is taken of the size of 6 cm x 6 cm x 4 cm. The Reynolds number for the flow in respect of the height of the cube i.e, 4 cm is 5.3x104. The hexahedral grids are used for the meshing of the flow domain. The results are discussed in terms of various parameters such as velocity profile around the cube and the computational domain, the pressure distribution over the cube, near wall velocity profile and the shear stress distribution and also the result of drag coefficient is verified by neural network time series analysis using MATLAB. In this present study we have used the OpenFoam platform for the computational and numerical analysis. The numerical scheme employed is the combination of the steady state incompressible Newtonian flow model using SIMPLE algorithm followed by the transient model of incompressible Newtonian flow using PISO algorithm. We have observed that there is a constant positive drag coefficient in case of steady state simulation where as there is a negative lift coefficient in the initial run and a very low lift coefficient at the end of the steady state simulation.
Applications of Differential Equations in Petroleum EngineeringRaboon Redar
In modern science and engineering, differential equations are very important. Nearly all known physics and chemistry laws are indeed differential equations. Engineers, in order to investigate systems behavior, it is virtually necessary that they are able to model and solve physical problems with mathematical equations.
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HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
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1. Reprinted: 24-03-2001 Report 0809-P, November 1988,
Website: www.shipmotions.nl Delft University of Technology,
Ship Hydromechanics Laboratory,
Mekelweg 2, 2628 CD Delft,
The Netherlands.
Model Experiments on Jack-Up Platform Hydrodynamics
J.M.J. Journée, W.W. Massie, B. Boon and R. Onnink
1. INTRODUCTION fatigue testing of joints, computer
simulations and reliability analysis using
This report describes the experiments also non-linear effects.
carried out with two simplified models Since the design of any structure today
showing the principals of elevated jack- involves computer simulations, the
up platforms. The purpose of these computer simulation of the non-linear
experiments is to investigate dynamic behaviour of an elevated jack-
hydrodynamic as well as structural non- up platform will play an important role
linearities in the interaction between the in the total project. Proper representation
structure and water. of the hydrodynamic interaction of the
As such, this model design and testing structure with the sea is essential for the
program forms a first step in an intended success of a dynamic simulation. This is
series of hydrodynamic model and therefore one of the first items to be
possibly prototype measurements of investigated, at least in a preliminary
hydrodynamic forces and dynamic way.
structural response of jack-up platforms The model tests described here are
in both regular and irregular waves. The intended to provide significant insight
whole series of these hydrodynamic into the non- linearities involving the
measurements is in turn, only a part of conversion from hydrodynamics to
the entire project to investigate the forces acting on jack-ups and the
dynamic behaviour and fatigue life of influence of the structural response on
jack-up platforms in order to develop those loads. Also they will provide a first
more appropriate design criteria and set of data against which a non-linear
evaluation methods for such platforms. computer simulation can be checked.
This involves also diverse topics such as
1
2. 2. MODEL DEFINITION A more correct dynamic simulation may
have to take into account relative rather
Purpose of the Experiments than absolute water particle velocities, in
other words take into account the
The traditional quasi-static calculation of interaction between hydrodynamic loads
the response of a jack-up to waves is and structural responses.
based upon the following assumptions: To gain some information to make this
• A description of hydrodynamic latter approach possible model
forces, determined for an (assumed) experiments are necessary. In particular
fixed structure from the local flow these are required when wave
conditions, using a linearised frequencies are approaching the natural
Morison equation. frequency of the jack-up and response
• A design wave (one wave with a motion amplitudes do have an
certain height and period) approach appreciable influence on the relative
is used, while a possible current is water particle velocity.
taken into account by adding the
current velocity to the wave particle Model Particulars
velocities.
• A rigid deck, with rigid deck-leg As explained above, the purpose of the
connections and legs hinged (or model tests is to gain insight in a
fixed) at the seabed. situation where structural motion
• A geometric non-linearity, which response will have significant impact on
occurs with jack-ups as a result of the relative water particle velocities.
secondary moments generated when Also it is important to investigate the
the deck load becomes eccentric to platform behaviour for wave frequencies
the reaction forces during dynamic in the vicinity of the resonant frequency
horizontal displacements. of the platform. These requirements to a
large degree dictate the dimensioning of
The response to irregular rather than the model. It is deemed advisable to use
regular waves is often determined by maximum possible model dimensions,
adding the wave particle velocities of the which are dependent on the available test
individual waves and the current, and facilities.
using this combined velocity in the For these experiments use has been
Morison formula. made of Towing Tank I of the Ship
A dynamic calculation of the response Hydromechanics Laboratory during a
can be performed in two different ways. period that a new one replaced the
The first method is a time domain towing carriage. Because of these
simulation of the structural response activities the maximum available water
using the absolute water particle depth in the basin was restricted to about
velocities as input into the Morison 2 meters.
formula. The other method is a This 2.0 meters depth dictated a leg
simulation in the frequency domain length slightly more than that. Waves
using a linearised Morison approach and possible in the basin had a frequency
a dynamic amplification for each ranging from about 0.7 until 1.3 Hz and
individual wave. a wave amplitude up to about 0.040
meter. The full range possible was used
2
3. in the tests. In order to avoid about 1.0 seconds the leg spacing was
complications in this stage of the taken as 0.700 meter.
research program it was decided to
provide no rotation restraint at the leg
footing.
With the diameter as a variable the
hydrodynamic loads were determined,
neglecting the role of roughness. In full
scale it is common in a quasi-static
calculation to allow maximum
deflections of a jack-up platform in the
order of 2 percent of the free leg length
for maximum design conditions. It was
decided to aim for similar deflections in
the maximum model test conditions.
This, together with an average wave
period of 1.0 seconds and a maximum
wave amplitude of 0.040 meter, dictated
the E ⋅ I value for the legs for various
leg diameters. Given a leg diameter and
E ⋅ I value, the leg wall thickness only
depends upon the elasticity modulus of
the leg material chosen. Realistic values
Table 1 Dimensions of the 3 Models
were found for relatively large diameter
PVC legs and small diameter copper
legs.
As the model should be tested around its
resonance a platform natural period of
around 1.0 seconds, being the average
wave period, was considered to be
necessary. With the leg dimensions and
materials given this dictated the mass of
the deck structures for the two models.
Two different deck masses for the
slender leg jack-up model were decided
upon, in order to check the influence on
the response of a shift in platform
natural frequency and the impact of the
second order leg bending. It was
checked that buckling risk would be
non-existent. The leg spacing was
determined by the whish to study
possible total load cancellation as a
result of spatial phase differences in the
hydrodynamic loading of the various
legs. Based upon a mean wave period of Figure 1 Model Dimensions
3
4. where interaction between those is
The dimensions of the jack-up models important.
are shown in Table 1 and Figure 1.
Dimensions of the Three Models
Model Dimensions
Pictures of Model No 1 in Experimental
Set-Up
3. EXPERIMENTAL SET-UP
The time and budget limitations for this
test series prevented the design or
purchase of specialised instrumentation.
The project was set up for "off the shelf"
instrumentation. Such equipment was
available at the Ship Hydromechanics
Laboratory for the measurement of
forces, accelerations and displacements.
However, none of these was designed
for submerged operation.
Figure 2 Pictures of Model No. 1 in Forces
Experimental Set-UP
Nine dynamometers, based on strain-
Figure 2 shows two pictures taken from gauge measurement of bending resulting
model number 1 in the towing tank, from shear forces, were coated with a
before filling the tank with water. flexible water proofing material so that
they could be used while submerged.
Model Scale Experience had already been gained with
this in other tests. These newly coated
It is important to note that these models units were first tested and calibrated
are not intended to represent actual full- before installation in the present set-up.
scale jack-ups. Rather they should be The results of the calibrations are iven in
considered as very small jack-ups at Appendix I.
scale 1:1. Thus scale effects are non- Force measurements were limited to the
existent. Nevertheless these small jack- registration of the force components
ups possess characteristics that are along each of the three axes with the
comparable to those of normal sized origin at the base of each leg A, B or C:
jack-ups. They allow studying the • x along the tank, positive toward the
special features that are subject of the wave maker
present research, i.e. the effect of non- • z vertical, positive upwards
linearities in wave loading and responses • y perpendicular to these according to
in the area near platform resonance a right-handed axis system.
4
5. The flexibility of the legs precluded that
the static indeterminance of the system These nine dynamometers were labeled
caused problems. Careful attention to Ax, Ay, Az, Bx, By, Bz, Cx, Cy and Cz
dimensions as well as installation respectively. The corresponding
procedures made it possible to keep such measured forces were denoted XA, YA,
resulting residual loads within a range ZA, XB, YB, ZB, XC, YC and ZC,
which could be discounted via the respectively.
calibration and balancing. A tenth dynamometer Dx was used to
The leg hinges and dynamometers are measure the forces due to waves on the
shown in the figures below. legs with the platform held motionless.
The dynamometer was fixed in space
and connected with the platform at
location D of the deck by means of a
double cardanic coupling mechanism.
This force was indicated by XD and the
results of the calibration of
dynamometer Dx are given in Appendix
I.
Accelerations and Displacements
Figure 3 Picture of Leg Hinges and An 5-g accelerometer was mounted on
Dynamometers the deck in such a way that it measured x
and y components of the acceleration at
the location D at the deck of the
platform. These accelerations were
indicated by x D and &&D .
&& y
Additionally a bit redundantly, the
horizontal x and y displacements of the
deck were measured at locations A and
C, so as to detect any possible rotations.
These displacements, indicated by x A, yA,
x C and yC., respectively, also provide for
a direct check of the acceleration
measurements.
Waves
A two-wire conductance wave probe, as
normally used in this towing tank,
measured the waves. The wave meter
was mounted adjacent to the platform so
that its record is in phase with that of the
"windward" leg A. This wave elevation
Figure 4 Close-Up Picture of Leg was indicated by ζ A .
Hinges and Dynamometers
5
6. Calibrations processing step will be the determination
of spectra for the various signals
The various measuring elements, such as recorded. In some cases both peak and
force meters, displacement meters and RMS values of the recorded (irregular)
accelerometers were individually signals will be of interest.
calibrated before installation. The results Data from a number of the runs will be
of these calibrations are summarised in used to check the computer simulations.
Appendix I. Later calibrations were only This can be done both with regular and
carried out in a more direct way. irregular waves.
The natural frequency of the platform
has been determined. Since model 1 has Regular Waves
first been installed in a dry tank, it was
possible to determine its natural Results of experiments carried out in
frequency both in air and in still water. regular waves, using at least three
For models 2 and 2-M only a natural different wave heights and a range of
frequency determination in still water wave periods which includes the natural
was possible. period of the structure in water, will be
used to determine the basic response of
each structure.
4. TESTING PROGRAM If the behaviour is completely linear,
then a plot of deck displacement
General Purpose amplitude divided by the wave
amplitude versus wave frequency will
The general purpose of the testing yield a family of identical curves,
program was to determine the influence showing the well-known resonance
of the platform motion response on the peak. The degree to which these curves
hydrodynamic non-linearity as are individual, thus wave amplitude
manifested via quadratic drag and the dependent, is a indication of the non-
ensuing impact on the superposition linearity of the situation.
principle as often used in naval
architecture. The results of this work are Non-linearities such as quadratic drag
essential for the description of the lead to the phenomena that a wave
hydrodynamics of jack-up platforms, to (input) at one frequency yields force
be used in computer simulations. components (output) at this same
Data from the various test runs were frequency as well as at higher harmonies
recorded in an analog form, so that it of this. Conversely, the presence of extra
may be worked out in a variety of ways energy at high frequencies in output as
in the future. Additionally, significant compared to input can be an indication
data were simultaneously displayed of non-linear behaviour. Force
visually on an UV paper-tape recorder as components in the y-direction can imply
a check. the presence of lift forces. However,
these are only expected to be of small
The "traditional naval architects amplitude, in particular for the model
approach" of examining only the first with the large diameter legs.
harmonics of responses was not
followed in these tests. One standard
6
7. Paired Regular Waves Before starting the experiments in
waves, the platform deck of model
A first check of the superposition number 1 was loaded by static forces in
principle, which makes the study of a the x-direction. The resulting vertical
linear(ised) system so attractive, is to forces at the hinged connection of the
expose the models to a wave consisting three legs to the bottom, ZA, ZB and ZC
of a superposition of two regular waves were measured. The results are given in
of different frequency as used above. Figure 5. It is clear that the sum of these
Such paired waves, themselves, show a measured vertical forces, ZA+ZB+ZC, has
well-known beat pattern with alternating to be zero. However the figure shows
segments of large and small amplitude. that a force of about 5 N remains.
The wave frequencies were chosen such
that they "embrace" the natural Figure 6 shows the displacements in the
frequency of the model; one frequency is x-direction, due to these static loads in
below the natural frequency and one the x-direction.
above it. If linearity and superposition is
preserved, then the result of this test Figure 7 shows the amplitudes of the
should be predictable from the results horizontal displacement in the x-
with regular waves. direction of the platform deck of model
number 1 in simple regular waves with
Wave Spectra Response three different nominal amplitudes.
The response of the model to waves Figure 8 shows the amplitudes of a wave
having a known, so measured, energy force component measured at the deck
spectrum was also determined. It is not level of the fixed model number 2 in
deemed necessary to generate a wave simple regular waves with one nominal
spectrum in the model, which exactly amplitude.
satisfies a theoretical model such as that
determined by the mean JONSWAP Figure 9 shows the amplitudes of the
spectrum. The linearised response horizontal displacement in the x-
function, determined by dividing the direction of the platform deck of this
output spectrum by the input wave model in simple regular waves with five
spectrum can be compared to that nominal amplitudes. These force and
determined using regular waves. displacement amplitudes are also shown
for model number 2-M in the Figure 10
5. SELECTED EXPERIMENTAL and Figure 11 for three nominal wave
RESULTS amplitudes.
As a check a few selected experimental Figure 12 shows the horizontal
results, derived from the UV recordings, deflections of the platform deck of
were examined during the experiments. model number 2, due to a static
The data, used for this purpose, are horizontal load on the platform deck in
tabulated in the summary of the the x-direction. These horizontal
experiments in Appendix I. These results deflections are also shown for model
are given below in graphs without number 2-M in Figure 13.
detailed discussion.
7
8. Figure 7 Amplitude of the Horizontal
Displacement in the x-Direction of the
Platform Deck of Model No 1 in
Simple Regular Waves
Figure 5 Vertical Reaction Forces
due to a Static Horizontal Load in the
x-Direction on the Platform Deck of
Model No 1 Figure 8 Amplitude of a Wave Force
Component of Model No 2 in Simple
Regular Waves
Figure 6 Horizontal Deflection of the Figure 9 Amplitude of the Horizontal
Platform Deck of Model No 1, due to a Displacement in the x-Direction of the
Static Horizontal Load in the x- Platform Deck of Model No 2 in
Direction on the Platform Deck Simple Regular Waves
8
9. Figure 13 Horizontal Deflections of
Figure 10 Amplitude of a Wave the Platform Deck of Model No 2-M,
Force Component of Model No 2-M in due to a Static Horizontal Load in the
Simple Regular Waves x-Direction on the Platform Deck
6. ACKNOWLEDGEMENT
The authors are indebted to Dr. Sv.
Spassov (Research Fellow from the
Bulgarian Ship Hydrodynamics Centre
in Varna) and Mr. P.J. Spaargaren
(student-assistant of the Faculty of Civil
Engineering) for their contributions to
Figure 11 Amplitude of the this project; especially for the
Horizontal Displacement in the x- dimensioning of the jack-up models.
Direction of the Platform Deck of Their work has been reported in an
Model No 2-M in Simple Regular Internal Technical Report of the Ship
Waves Hydromechanics Laboratory:
Spassov Sv. and P.J. Spaargaren
On Jack-Up Platforms and
Marine Riser Dynamics,
Delft University of Technology,
Ship Hydromechanics
Laboratory, Report No. 0793-M,
May 1988.
APPENDIX I:
SUMMARY OF EXPERIMENTS
Figure 12 Horizontal Deflections of
the Platform Deck of Model No 2, due The experiments were carried out in
to a Static Horizontal Load in the x- Towing Tank Number I of the Ship
Direction on the Platform Deck Hydromechanics Laboratory during the
months July and August 1988.
9
10. The width of this tank is 4.200 meter. Channel 02: force signal ZA
The water depth was 2.004 meter during Channel 03: force signal XB
all experiments and the constant Channel 04: force signal ZB
temperature of the fresh water was about Channel 05: force signal XC
17.0 0 C. Channel 06: force signal ZC
The experiments were carried out with Channel 07: displacement signal x A
three jack-up models, in order numbered Channel 08: displacement signal x C
by 1, 2 and 2-M. Jack-up number 2-M is Channel 09: displacement signal yA
identical to jack-up number 2, but Channel 10: displacement signal yC
masses of 1.05 kg are added at the deck Channel 11: not available
level on the centerline of each leg. Channel 12: &&
acceleration signal x D
The axis system and the location are Channel 13: wave elevation signal ζ
given in the figure below.
The tape speed was 17/8 inch per second.
The signals on channels 12 and 13 were
recorded directly, via a modulator-
demodulator. A reference voltage of
± 2 Volt or ± 1 Volt was given on the
tapes regularly too. All required
information for data processing, such as
calibration data, amplification factors,
Figure 14 Axis System and Location
etc., was stored on the voice channel of
in Towing Tank I
the recorder.
An UV paper-tape recorder was used for
The calibration factors of the 9
registration of the various signals as
dynamometers at the lower leg-ends are
listed below:
listed below:
A x: 1 Volt = 46.2 N Channel 01: acceleration signal &&Dy
A y: 1 Volt = 42.7 N Channel 02: acceleration signal x D&&
Az: 1 Volt = 41.5 N (also on IR)
Bx : 1 Volt = 47.8 N Channel 03: displacement signal x C
By : 1 Volt = 43.6 N (also on IR)
Bz : 1 Volt = 46.6 N Channel 04: displacement signal x A
C x: 1 Volt = 44.7 N
(also on IR)
C y: 1 Volt = 43.0 N
Channel 05: displacement signal yC
Cz: 1 Volt = 44.8 N
The calibration factor of the (also on IR)
dynamometer used to measure the force Channel 06: displacement signal y A
in the space-fixed top-side of the (also on IR)
platform, caused by the wave forces, is Channel 07: force signal Y A
given by: or force signal X D
Dx : 1 Volt = 20.0 N
An instrumentation recorder was used Channel 08: force signal YC
for registration of the various signals as Channel 09: force signal Y B
listed below: Channel 10: not available
Channel 01: force signal XA
10
11. Channel 11: wave elevation signal ζ
(also on IR) For a few runs an enlarged scale was
Channel 12: not used used for the wave elevation signal on the
paper-tape. This is marked in the tables
The standard calibration factors of these with a comment.
signals are as follows: When looking in the direction opposite
ζ: 1.0 cm = 1.0 cm on UV the paper transport, (standing in front of
the recorder) the positive direction of the
x A : 1.0 cm = 2.0 cm on UV
signals is a movement from left to right
y A : 1.0 cm = 2.0 cm on UV on the UV recorder. Left is also defined
x C : 1.0 cm = 2.0 cm on UV by the numbered side of the paper-tape.
yC : 1.0 cm = 2.0 cm on UV
During the experiments in irregular
&&
x D : 1.0 g = 14.14 cm on UV
waves the transient time after starting the
&&D : 1.0 g = 14.14 cm on UV
y generation of the waves and before
YA : 1.0 V = 42.7 N = 5.0 cm on UV starting the registration of the signals
YB : 1.0 V = 43.6 N = 5.0 cm on UV was about three minutes. This was done
to get a proper registration of the
YC : 1.0 V = 43.0 N = 5.0 cm on UV
behaviour of the platform. For each run
X D of jack-up number 1: in irregular waves the measuring time
1.0 V = 20.0 N = 1.0 cm on UV was about 20 minutes.
X D of jack-up number 2 and 2-M:
1.0 V = 20.0 N = 4.5 cm on UV
11
12. APPENDIX II: TABLES WITH EXPERIMENTAL DATA
In the following tables all experiments are listed in the order as they have been carried
out. In these tables some runs are marked with "free oscillation". These experiments
were carried out in still water. If no counter reading is given, then the signals were
recorded on the UV paper-tape recorder only.
The mark "reference signal" means that a reference voltage of ± 2 Volt or ± 1 Volt was
given on the instrumentation recorder.
12