Hjulstrom Curve(Terms)
1. Capacity: largest amount (weight) of debris that the river can carry.
2. Competence: diameter of the largest particles (size) that can be carried.
3. Critical erosion velocity: lowest velocity at which grain of a given size can be moved.
4. Settling/fall velocity: velocity falls below certain level particle (fall velocity) will be deposited.
Hjulstrom Curve
The Hjulstrøm curve is a graph used by hydrologists to determine whether a river will erode, transport, or deposit sediment.
The Hjulstrom curve is a graph that shows the relationship between the velocity of a river and the particle sizes that may be transported.
It shows the velocity needed to pick up material of a certain size (velocity needed for erosion to take place), and the settling velocity when deposition will occur.
Interpretation of the Hjulstrom curve/graph.
The x-axis shows the size of the particles in mm.
The y-axis shows the velocity of the river in cm/s.
Hjulstrom graph shows relationship between stream velocity and ability to transport materials of varying sizes. (i.e. finest
particles; clay & silt to largest boulders)
There are two curves lines drawn in a Hjulstrom curve; critical erosion velocity and settling or fall velocity.
Hjulstrom Curve(Terms)
1. Capacity: largest amount (weight) of debris that the river can carry.
2. Competence: diameter of the largest particles (size) that can be carried.
3. Critical erosion velocity: lowest velocity at which grain of a given size can be moved.
4. Settling/fall velocity: velocity falls below certain level particle (fall velocity) will be deposited.
Hjulstrom Curve
The Hjulstrøm curve is a graph used by hydrologists to determine whether a river will erode, transport, or deposit sediment.
The Hjulstrom curve is a graph that shows the relationship between the velocity of a river and the particle sizes that may be transported.
It shows the velocity needed to pick up material of a certain size (velocity needed for erosion to take place), and the settling velocity when deposition will occur.
Interpretation of the Hjulstrom curve/graph.
The x-axis shows the size of the particles in mm.
The y-axis shows the velocity of the river in cm/s.
Hjulstrom graph shows relationship between stream velocity and ability to transport materials of varying sizes. (i.e. finest
particles; clay & silt to largest boulders)
There are two curves lines drawn in a Hjulstrom curve; critical erosion velocity and settling or fall velocity.
Effects of Food Tocotrienol Substances on Serum Cholesterol level of Adult (Premenopausal) Women Consuming Fast Food (Hamburger) in Developed City (Owerri) of Imo State, Nigeria.
Ficha Técnica de la Compañía Graña y Montero SAAGrupo Coril
Ficha técnica de la compañía Graña y Montero con información financiera y bursátil actualizadas al Cuarto Trimestre del 2016 y al cierre de bolsa del 17 de febrero del 2017 respectivamente.
Optimization of Process Parameters in Turning Operation of AISI-1016 Alloy St...IOSR Journals
This paper investigates the parameters affecting the roughness of surfaces produced in the turning
process for the material AISI-1016 Steel. Design of experiments was conducted for the analysis of the influence
of the turning parameters such as cutting speed, feed rate and depth of cut on the surface roughness. The
results of the machining experiments for AISI-1016 were used to characterize the main factors affecting
surface roughness by the Analysis of Variance (ANOVA) method. The feed rate was found to be the most
significant parameter influencing the surface roughness in the turning process.
Review on Design Optimization of Liquid Carrier Tanker for Reduction of Slosh...IOSR Journals
Abstract: This Paper Reviews Briefly The Current Research On Sloshing And Its Effect In Liquid Carrier
Tanker. The Aim Of This Paper To Study The Basics Of Sloshing And Its Prevention (Mainly In Liquid Carrier
Tanker) The Liquid Sloshing Is Free Surface Fluctuation Of Liquid When Its Container Is Excited By External
Vibrations Such As Earthquakes. The Liquid Sloshing May Cause Various Engineering Problem, For Example
Instability Of Ships In Aero Engineering And Ocean Engineering, Failures On Structural Systems Of The
Liquid Container. The Tanker Used For The Transportation Of Liquid Over The Road-Ways Is An Integral
Part Of The Carrier/Vehicle. The Tanker Is Expected To Withstand The Unbalanced Forces On Account Of
Transit Over Uneven And Irregular Surfaces/Contours Of The Road As Also Due To Sudden Acceleration Or
Deceleration (Due To Application Of Brakes).
Keywords-Sloshing, Impact, Baffle, Simulation
Computational Aerodynamics Research and Vehicle Engineering Development (CAR-...inventionjournals
Many Persons, both from industry and also private individuals have performed research in regards to this new issue. Many have performed research on aerodynamics on certain portions of the vehicle and also on effects of shape of the body and other technologies used such as Computational Fluid Dynamics and Wind tunnel Testing.The effects of these studies is seen in the industry today. Not so long ago,the vehicles were having shapes lose to boxes and today beautiful curves dominate the vehicles bodies. These curves not only help in the beauty of the vehicle but also help the vehicle in terms of aerodynamics and fuel efficiency. In this paper we would like to highlight some important topics related with aerodynamics and how they affect the drag of the vehicles. We shall also discuss on methods used in the industry today to calculate the aerodynamic efficiency of the vehicles and their effects.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Drag Optimization of Bluff Bodies using CFD for Aerodynamic Applicationsijceronline
This paper deals with the optimization of bluff bodies and analysis of fluid flow behaviour around bodies using CFD. Three test cases of bluff bodies; mainly two-dimensional rectangular body, radial rectangular shape and bullet shaped body were considered in this paper. Their shapes were optimised to achieve aerodynamic body shape using drag coefficient as main criteria. The other aerodynamic characteristics like formation of different eddy loops due to eddy viscosity, lift force coefficient and pressure force with Mach number were also investigated. It is concluded that aerodynamically; bullet shaped body is best among all the cases
UNMANNED SURFACE VEHICLE (USV) FOR COASTAL SURVEILLANCEIAEME Publication
The purpose of this paper is to design and fabricate an unmanned surface vehicle (USV) for the coastal surveillance for the maritime of India. It aims to monitor territorial waters on a round-the-clock basis and allows the intelligence to take appropriate action to prevent terrorism, illegal smuggling and human trafficking as the continuous use of an aircraft for surveillance is prohibitively expensive along the Indian coastline which is a massive stretch measuring 7,517km.In this paper an Air Cushioned Vehicle (ACV) popularly known as a Hovercraft is chosen for surveillance as it has the ability to traverse any surface compared to other coastguard vessels thereby earning the title of amphibious boats. Its ability to access 75% of littoral allows them to come on shore during emergencies unlike conventional coastguards that have only 5% littoral access and cannot enter shallow water.
This work presents hydrodynamic characterization and comparative analysis of high speed crafts
(HSCs). HSCs performance characterizing is a serious concern to Hydrodynamicists because of the wide
variation of total resistance with hull-form, trim, draft and speed. Conversely, these parameters are not duly
analyzed during design due to inadequate theories. Therefore, this research investigates total resistance, wetted
surface and effective trim of four different HSC hull-forms. An interactive computer-program is developed based
on Savitsky and CAHI algorithms, and the results compared against test-data. The analysis correctly predicts
quantitatively the resistances of the four hull-forms at high speeds but with some discrepancies at speeds below
12 knots. The average standard-deviation for resistance predictions by CAHI = 4.69 kN and Savitsky= 6.13 KN.
Also, the results indicate that the transition from bow-wetting to full-planing occurs at 12 knots, and beyond
which the effective trim is fairly constant. Again, the wetted length-beam ratio (λm) drops rapidly from bowwetting
speeds to a plateau at speeds >12knot where hydrodynamic lift prevails. Standard-deviations of λm by
Savitsky’s and CAHI are 1.07 and 1.41, respectively. In conclusion, model-predictors are reasonably in good
agreement with measurement.
Effects of Food Tocotrienol Substances on Serum Cholesterol level of Adult (Premenopausal) Women Consuming Fast Food (Hamburger) in Developed City (Owerri) of Imo State, Nigeria.
Ficha Técnica de la Compañía Graña y Montero SAAGrupo Coril
Ficha técnica de la compañía Graña y Montero con información financiera y bursátil actualizadas al Cuarto Trimestre del 2016 y al cierre de bolsa del 17 de febrero del 2017 respectivamente.
Optimization of Process Parameters in Turning Operation of AISI-1016 Alloy St...IOSR Journals
This paper investigates the parameters affecting the roughness of surfaces produced in the turning
process for the material AISI-1016 Steel. Design of experiments was conducted for the analysis of the influence
of the turning parameters such as cutting speed, feed rate and depth of cut on the surface roughness. The
results of the machining experiments for AISI-1016 were used to characterize the main factors affecting
surface roughness by the Analysis of Variance (ANOVA) method. The feed rate was found to be the most
significant parameter influencing the surface roughness in the turning process.
Review on Design Optimization of Liquid Carrier Tanker for Reduction of Slosh...IOSR Journals
Abstract: This Paper Reviews Briefly The Current Research On Sloshing And Its Effect In Liquid Carrier
Tanker. The Aim Of This Paper To Study The Basics Of Sloshing And Its Prevention (Mainly In Liquid Carrier
Tanker) The Liquid Sloshing Is Free Surface Fluctuation Of Liquid When Its Container Is Excited By External
Vibrations Such As Earthquakes. The Liquid Sloshing May Cause Various Engineering Problem, For Example
Instability Of Ships In Aero Engineering And Ocean Engineering, Failures On Structural Systems Of The
Liquid Container. The Tanker Used For The Transportation Of Liquid Over The Road-Ways Is An Integral
Part Of The Carrier/Vehicle. The Tanker Is Expected To Withstand The Unbalanced Forces On Account Of
Transit Over Uneven And Irregular Surfaces/Contours Of The Road As Also Due To Sudden Acceleration Or
Deceleration (Due To Application Of Brakes).
Keywords-Sloshing, Impact, Baffle, Simulation
Computational Aerodynamics Research and Vehicle Engineering Development (CAR-...inventionjournals
Many Persons, both from industry and also private individuals have performed research in regards to this new issue. Many have performed research on aerodynamics on certain portions of the vehicle and also on effects of shape of the body and other technologies used such as Computational Fluid Dynamics and Wind tunnel Testing.The effects of these studies is seen in the industry today. Not so long ago,the vehicles were having shapes lose to boxes and today beautiful curves dominate the vehicles bodies. These curves not only help in the beauty of the vehicle but also help the vehicle in terms of aerodynamics and fuel efficiency. In this paper we would like to highlight some important topics related with aerodynamics and how they affect the drag of the vehicles. We shall also discuss on methods used in the industry today to calculate the aerodynamic efficiency of the vehicles and their effects.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Drag Optimization of Bluff Bodies using CFD for Aerodynamic Applicationsijceronline
This paper deals with the optimization of bluff bodies and analysis of fluid flow behaviour around bodies using CFD. Three test cases of bluff bodies; mainly two-dimensional rectangular body, radial rectangular shape and bullet shaped body were considered in this paper. Their shapes were optimised to achieve aerodynamic body shape using drag coefficient as main criteria. The other aerodynamic characteristics like formation of different eddy loops due to eddy viscosity, lift force coefficient and pressure force with Mach number were also investigated. It is concluded that aerodynamically; bullet shaped body is best among all the cases
UNMANNED SURFACE VEHICLE (USV) FOR COASTAL SURVEILLANCEIAEME Publication
The purpose of this paper is to design and fabricate an unmanned surface vehicle (USV) for the coastal surveillance for the maritime of India. It aims to monitor territorial waters on a round-the-clock basis and allows the intelligence to take appropriate action to prevent terrorism, illegal smuggling and human trafficking as the continuous use of an aircraft for surveillance is prohibitively expensive along the Indian coastline which is a massive stretch measuring 7,517km.In this paper an Air Cushioned Vehicle (ACV) popularly known as a Hovercraft is chosen for surveillance as it has the ability to traverse any surface compared to other coastguard vessels thereby earning the title of amphibious boats. Its ability to access 75% of littoral allows them to come on shore during emergencies unlike conventional coastguards that have only 5% littoral access and cannot enter shallow water.
This work presents hydrodynamic characterization and comparative analysis of high speed crafts
(HSCs). HSCs performance characterizing is a serious concern to Hydrodynamicists because of the wide
variation of total resistance with hull-form, trim, draft and speed. Conversely, these parameters are not duly
analyzed during design due to inadequate theories. Therefore, this research investigates total resistance, wetted
surface and effective trim of four different HSC hull-forms. An interactive computer-program is developed based
on Savitsky and CAHI algorithms, and the results compared against test-data. The analysis correctly predicts
quantitatively the resistances of the four hull-forms at high speeds but with some discrepancies at speeds below
12 knots. The average standard-deviation for resistance predictions by CAHI = 4.69 kN and Savitsky= 6.13 KN.
Also, the results indicate that the transition from bow-wetting to full-planing occurs at 12 knots, and beyond
which the effective trim is fairly constant. Again, the wetted length-beam ratio (λm) drops rapidly from bowwetting
speeds to a plateau at speeds >12knot where hydrodynamic lift prevails. Standard-deviations of λm by
Savitsky’s and CAHI are 1.07 and 1.41, respectively. In conclusion, model-predictors are reasonably in good
agreement with measurement.
presentation is made with a view to simplify the understanding of fluid mechanics ( fluid kinematics is given more credit ) in civil engineering - mechanical engineering - body science
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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.
Abstract - Computational Fluid Dynamics Study of a Hull of an Autonomous Underwater Vehicle Glider
1. Abstract
Glider autonomous underwater vehicles are vehicles that move vertically controlling its
buoyancy, and horizontally due to the presence of wings. When they reach the surface, these
vehicles decrease its buoyancy entering a dive while its external shape produces horizontal
motion. Reaching the point of maximum depth, these vehicles become less dense than the
surrounding water, causing them to move vertically to the surface and again horizontally due to
its outer shape and essentially the presence of the wings.
The flow of water around the hull of an autonomous underwater vehicle creates an interaction
between them, which translates into forces and moments. These originate from the pressure
field around the hull and the viscous friction tensions on the surface of the hull. For the study of
the interaction of the fluid with the hull of the vehicle, CFD analysis is an adequate tool.
The reason of this thesis arises within a previous work master’s degree [1], whose main objective
was to conceptually design a platform able to accommodate all sensors and systems necessary
for the operation of an autonomous underwater vehicle. This work resulted from a collaboration
between the University of Beira Interior (UBI) and the University of ST. Thomas (UST).
This paper presents a CFD study of the interaction of a fluid with the hull of an autonomous
underwater gliding vehicle, in order to develop a new body with a reduced hydrodynamic drag.
To perform CFD analysis on the bodies subject to analysis, it is essential to generate a
computational domain, containing the elements or cells in which the flow is solved, and to
choose of an appropriate turbulence model.
Similar studies have been discussed by others in order to optimize bodies suitable for this type
of vehicle, involving the development of optimization algorithms, reduction the requirement for
propulsive power by drawing new geometries with reduced drag. However, the studies found in
the literature deal with propeller propulsion cases operating at higher Reynolds numbers. Thus,
making the present case a relevant problem.
Slender bodies and axy-symmetric, with smooth contours geometry, are the most appropriate
for autonomous underwater vehicles, when it comes to low Reynolds numbers. The transverse
dimension of these bodies is much lower than its longitudinal dimension, preventing separation
of the laminar boundary layer in the afterbody in normal operation.
Keywords
Fuselages, Autonomous Underwater Vehicles, Computational Fluid Dynamics (CFD),
Underwater Glider