The document summarizes an experimental study that investigated the wind load on hexagonal cylinders. Static pressure distributions were measured on single and paired hexagonal cylinders in a wind tunnel at various wind speeds and angles of attack. Lower drag and lift forces were observed for hexagonal cylinders compared to square cylinders, approaching the lower values seen for circular cylinders. It was concluded that hexagonal cylinders experience significantly lower wind loads than square cylinders of the same width.
Design and analysis of reinforced concrete multistory commercial building usi...Estisharaat Company
Design of multistory building by solving a sample manually ans rest of the building by solving on autodesk robot analysis, complete detailing of r.c members,final year project,complete ,how to design slabs, how to design beams, how to design rc column, how to make final year project, design of stairs,how to design foundations , how to prepare a project before using it in software for analysis,
Design and analysis of reinforced concrete multistory commercial building usi...Estisharaat Company
Design of multistory building by solving a sample manually ans rest of the building by solving on autodesk robot analysis, complete detailing of r.c members,final year project,complete ,how to design slabs, how to design beams, how to design rc column, how to make final year project, design of stairs,how to design foundations , how to prepare a project before using it in software for analysis,
General provisions for structureal steel building and structure (bnbc)Ferdous Kabir
General Provisions for Structural Steel Building and Structure (BNBC)
This section states the scope of the specification summarizes reference specification, Code and standard document and provides requirements for material and contract document
Tower design using Dynamic analysis method is now became easier than ever with this simple and effective PDF manual. Starting from modeling, defining till computing results based on Dynamic Analysis you can build the tower of your dream.
Engineering is fun and so does this PDF !
The lecture is in support of:
(1) The Design of Building Structures (Vol.1, Vol. 2), rev. ed., PDF eBook by Wolfgang Schueller, 2016
(2) Building Support Structures, Analysis and Design with SAP2000 Software, 2nd ed., eBook by Wolfgang Schueller,
The SAP2000V15 Examples and Problems SDB files are available on the Computers & Structures, Inc. (CSI) website: http://www.csiamerica.com/go/schueller
Steel portal frames are very efficient and economical when used for
single-storey buildings, provided that the design details are cost effective and
the design parameters and assumptions are well chosen. In countries where this
technology is highly developed, the steel portal frame is the dominant form of
structure for single-storey industrial and commercial buildings. It has become
the most common structural form in pitched roof buildings, because of its
economy and versatility for a wide range of spans.
American Society of Civil Engineers
Minimum Design Loads for Buildings and Other Structures
2010
--------------------------
Te invito a que visites mis sitios en internet:
_*Canal en youtube de ingenieria civil_*
https://www.youtube.com/@IngenieriaEstructural7
_*Blog de ingenieria civil*_
https://thejamez-one.blogspot.com
Manual for Detailing Reinforced Concrete Structures to EC20984
Detailing is an essential part of the design process. This thorough reference guide for the design of reinforced concrete structures is largely based on Eurocode 2 (EC2), plus other European design standards such as Eurocode 8 (EC8), where appropriate.
With its large format, double-page spread layout, this book systematically details 213 structural elements. These have been carefully selected by José Calavera to cover relevant elements used in practice. Each element is presented with a whole-page annotated model along with commentary and recommendations for the element concerned, as well as a summary of the appropriate Eurocode legislation with reference to further standards and literature. The book also comes with a CD-ROM containing AutoCAD files of all of the models, which can be directly developed and adapted for specific designs.
Its accessible and practical format makes the book an ideal handbook for professional engineers working with reinforced concrete, as well as for students who are training to become designers of concrete structures.
In support of:
• Building Support Structures, Analysis and Design with SAP2000 Software, 2nd ed., eBook by Wolfgang Schueller, 2015. The SAP2000V15 Examples and Problems SDB files are available on the Computers & Structures, Inc. (CSI) website: http://www.csiamerica.com/go/schueller
• The Design of Building Structures (Vol.1, Vol. 2), rev. ed., PDF eBook by Wolfgang Schueller, 2016, published originally by Prentice Hall, 1996, 868 pages
This publication provides a concise compilation of selected rules in the Eurocode 8, together with relevant Cyprus National Annex, that relate to the design of common forms of concrete building structure in the South Europe. Rules from EN 1998-1-1 for global analysis, regularity criteria, type of analysis and verification checks are presented. Detail design rules for concrete beam, column and shear wall, from EN 1998-1-1 and EN1992-1-1 are presented. This guide covers the design of orthodox members in concrete frames. It does not cover design rules for steel frames. Certain practical limitations are given to the scope.
General provisions for structureal steel building and structure (bnbc)Ferdous Kabir
General Provisions for Structural Steel Building and Structure (BNBC)
This section states the scope of the specification summarizes reference specification, Code and standard document and provides requirements for material and contract document
Tower design using Dynamic analysis method is now became easier than ever with this simple and effective PDF manual. Starting from modeling, defining till computing results based on Dynamic Analysis you can build the tower of your dream.
Engineering is fun and so does this PDF !
The lecture is in support of:
(1) The Design of Building Structures (Vol.1, Vol. 2), rev. ed., PDF eBook by Wolfgang Schueller, 2016
(2) Building Support Structures, Analysis and Design with SAP2000 Software, 2nd ed., eBook by Wolfgang Schueller,
The SAP2000V15 Examples and Problems SDB files are available on the Computers & Structures, Inc. (CSI) website: http://www.csiamerica.com/go/schueller
Steel portal frames are very efficient and economical when used for
single-storey buildings, provided that the design details are cost effective and
the design parameters and assumptions are well chosen. In countries where this
technology is highly developed, the steel portal frame is the dominant form of
structure for single-storey industrial and commercial buildings. It has become
the most common structural form in pitched roof buildings, because of its
economy and versatility for a wide range of spans.
American Society of Civil Engineers
Minimum Design Loads for Buildings and Other Structures
2010
--------------------------
Te invito a que visites mis sitios en internet:
_*Canal en youtube de ingenieria civil_*
https://www.youtube.com/@IngenieriaEstructural7
_*Blog de ingenieria civil*_
https://thejamez-one.blogspot.com
Manual for Detailing Reinforced Concrete Structures to EC20984
Detailing is an essential part of the design process. This thorough reference guide for the design of reinforced concrete structures is largely based on Eurocode 2 (EC2), plus other European design standards such as Eurocode 8 (EC8), where appropriate.
With its large format, double-page spread layout, this book systematically details 213 structural elements. These have been carefully selected by José Calavera to cover relevant elements used in practice. Each element is presented with a whole-page annotated model along with commentary and recommendations for the element concerned, as well as a summary of the appropriate Eurocode legislation with reference to further standards and literature. The book also comes with a CD-ROM containing AutoCAD files of all of the models, which can be directly developed and adapted for specific designs.
Its accessible and practical format makes the book an ideal handbook for professional engineers working with reinforced concrete, as well as for students who are training to become designers of concrete structures.
In support of:
• Building Support Structures, Analysis and Design with SAP2000 Software, 2nd ed., eBook by Wolfgang Schueller, 2015. The SAP2000V15 Examples and Problems SDB files are available on the Computers & Structures, Inc. (CSI) website: http://www.csiamerica.com/go/schueller
• The Design of Building Structures (Vol.1, Vol. 2), rev. ed., PDF eBook by Wolfgang Schueller, 2016, published originally by Prentice Hall, 1996, 868 pages
This publication provides a concise compilation of selected rules in the Eurocode 8, together with relevant Cyprus National Annex, that relate to the design of common forms of concrete building structure in the South Europe. Rules from EN 1998-1-1 for global analysis, regularity criteria, type of analysis and verification checks are presented. Detail design rules for concrete beam, column and shear wall, from EN 1998-1-1 and EN1992-1-1 are presented. This guide covers the design of orthodox members in concrete frames. It does not cover design rules for steel frames. Certain practical limitations are given to the scope.
Download link: https://www.researchgate.net/publication/318852873_Engineering_Drawing_-_I
DOI: 10.13140/RG.2.2.22512.56328
An engineering drawing is a type of technical drawing, used to fully and clearly define requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature, interpretation, appearance size, etc.
Its purpose is to accurately and unambiguously capture all the geometric features of a product or a component. The end goal of an engineering drawing is to convey all the required information that will allow a manufacturer to produce that component.
This research is concerned with the nature and aerodynamic behavior on cricket balls in flight. It is written to determine the aerodynamic characteristics of a cricket ball with a mass of 156 gm and approximate diameter of 70 mm, where a sample cricket ball was fixed with a shaft in a wind tunnel. The aerodynamic characteristics have been analyzed by varying the rotational rpm of the cricket ball, where the axis of rotation for seam and shaft is same and the pressure difference between the upper and the lower surface of the cricket ball determine by the help of static manometer. Some experimental works have also been carried out and compared with those of the results obtained numerically. The upward pressure, which creates lift, has increased almost linearly with the increase of ball position angle to approximately 15o to 30o and it also decrease with increase of ball rotational speed. Finally some conclusions have been drawn on the basis of the experimental result.
Design Analysis Of Uav (Unmanned Air Vehicle) Using NACA 0012 Aerofoil ProfileDr. Bhuiyan S. M. Ebna Hai
This research work is concerned with the application of conceptual design of Unmanned Air Vehicle (UAV). UAV is used for surveillance and reconnaissance to serve for the defense as well as national security and intelligence purpose. Here NACA 0012 aerofoil profile is used to design UAV by using CFD (Computational Fluid Dynamics) software. The aim of this research is to investigate the flow patterns and determine the aerodynamic characteristics of NACA 0012 profile by varying the angle of attack and Reynolds Number numerically. The research is carried out with symmetric aerofoil with the chord length of 0.1m. The research work explained different aerodynamic characteristics like lift force and drag force, lift and drag coefficient, pressure distribution over aerofoil etc.
Flow Investigation inside A Curved Square DuctIJERA Editor
This paper presents the results of an experimental work with measurement of wall static pressure of 90°C shaped Curved duct. The test duct is made up of transparent perspex sheets to facilitate the flow visualization study. The duct has an inlet to exit area ratio of 1.0 with centerline distance of 750 mm. The inlet aspect ratio of the test duct has been fixed at 1.0. The velocities for the proposed investigations are to be measured by using a Pitot tube.Wall pressures are measured with the help of an inclinedmanometer with the inclination of 35°. The manometer had two tubes emanating from it: one left open to the atmosphere and the other connected to the steel pipes attached to the four walls of the curved duct. The difference in the readings helped us calculate the static pressure and thereby the normalized pressure. Wall pressure distribution along the curved and parallel walls of the duct at 0°, 22.5°, 45°, 67.5° and 90° measuring sections was measured. All the experimental data has been processed by an Intel i3 CPU, 3 GB RAM PC and analyzed to give the distribution of static pressure in the square duct.The main purpose of this investigation is to show the development of secondary flow which happens when the flow takes place through the bend in the curvature. This secondary flow arises as a result of a centrifugal force acting when the flow moves through the bend. The investigation is carried out at three different velocities 20 m/s, 40 m/s and 60 m/s. The distribution of normalized pressure which is the ratio of static pressure to the dynamic pressure is mapped and shown in the form of contours by using the software package SURFER.The trend of wall static pressure development on the walls of C shaped duct shows that as the flow proceeds towards the curvature, there exists a high pressure gradient between the outside face and inside face due the centrifugal force acting along the curvature. This shows the bulk shifting of flow towards the inside face. This is due to the generation of secondary motion in a plane perpendicular to the primary flow.
Analysis of cross flow induced vibration in an inline and staggered configura...eSAT Journals
Abstract
In many engineering applications like heat exchanger, radiator, evaporator, nuclear power plant and thermal power plant, arrangement of tubes is very crucial. Fluid elastic instability forms the basis for deciding the type of arrangement and tube spacing but the phenomenon of vortex induced vibration is random in nature. Tube spacing also plays a critical role in different types of arrangement. Different type of application requires different tube spacing and the range of tube spacing vary from 1 to 6. Vortex Induced Vibration in cross flow around the inline and staggered arrangement of the tube arrays is experimentally studied for varying P/d (tube spacing) ratio. It is observed that with the increase in the velocity, the amplitude displacement increases. As the amplitude displacement of the tube reduces, the pitch over diameter ratio is increased from 2 to 4. It is also observed that between inline and staggered arrangement, the amplitude displacement of staggered arrangement is more compared to inline arrangement for same tube spacing.
Keywords: Vortex Induced Vibration, Inline Arrangement, Staggered Arrangement, Regression Analysis
CFD Simulation of Swirling Effect in S-Shaped Diffusing Duct by Swirl Angle o...IOSR Journals
Abstract: The present study involves the CFD analysis for the prediction of swirl effect on the characteristics
of a steady, incompressible flow through an S-shaped diffusing duct BY KEEPING SWIRL ANGLE OF 10˚. The
curved diffuser considered in the present case has S-shaped diffusing duct having an area ratio of 1.9, length of
300 mm and turning angle of 22.5°/22.5°. The static pressure, total pressure, velocity and turbulence intensity
were accounted. The improvement is observed for both, clockwise and anti-clockwise swirl, the improvement
being higher for clockwise swirl. Flow uniformity at the exit is more uniform for clockwise swirl at the inlet.
Keywords: Curved diffusers, intake ducts, swirling flow, secondary flows, pressure recovery
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Computational Investigation of Flow Structure Within a Sinuous DuctIJERA Editor
In the present investigation the distribution of mean velocity are experimentally studied on three constant area
rectangular curved ducts with an aspect ratio of 2.4. First one is C-shape, second one is S-shape and third one
is a DS-shape duct. The experiment is carried out at mass averaged mean velocity of 40m/s for all the ducts.
The velocity distribution shows for C-duct, the bulk flow shifting from outer wall to the inner wall along the
flow passage and for S-duct, the bulk flow shifting from outer wall to the inner wall in the first half and from
inner wall to the outer wall in the second half along the flow passage of curved ducts are very instinct. Due to
the imbalance of centrifugal force and radial pressure gradient, secondary motions in the forms of counter
rotating vortices have been generated within both the curved duct. For DS-duct the velocity distributions shows
the Bulk of flow shifting from inner watt to outer wall in the first bend and third bend of the duct and outer wall
to inner wall in the second bend and forth bend of the duct along the flow passage is very instinct. Flow at end
of the DS-duct is purely uniform in nature due to non existence of secondary motion. The experimental results
then were numerically validated with the help of Fluent, which shows a good agreement between the
experimental and predicted results for all the ducts
Effect of Geometric Configuration on Performance of Uniflow CycloneIJERD Editor
Reverse flow cyclones find wide applications in many industries however, they require a high
expenditure of energy and large pressure drops, which can be better overcome by uniflow cyclones. A
laboratory unit of Uniflow Cyclone has been developed with 45 mm inlet diameter. The performance
parameters pressure drop and total efficiency were studied for the effect of geometric configuration. The present
study includes the effect of 4 different geometric parameters on performance of uniflow cyclone. The geometric
variation of test cyclones includes the Inlet velocity, Vane angles, Outlet to inlet diameter ratio and Separation
lengths. The overall experimental results yield and investigated the optimal conditions for uniflow cyclone
performance is 450 vane angle, 0.5 outlet to inlet diameter ratio, 3D separation length and 9-10 m/s inlet
velocity. The experimental pressure drop values are validated with the model equations available in literature
and well matched for Ramachandran model.
A Numerical study of Flow through Sigmoid DuctIJERA Editor
Curved diffusers are an integral component of the gas turbine engines of high-speed aircraft. These facilitate
effective operation of the combustor by reducing the total pressure loss. The performance characteristics of
these diffusers depend on their geometry and the inlet conditions. In the present investigation the distribution of
mean velocity, static pressure and total pressure are experimentally studied on a S-shape Diffusing Duct of
45°/45° angle of turn with an area ratio of 1.65 aspect ratio 3.95 keeping inlet width 55 mm with centre line
length 460 mm. The experimental results then were numerically validated with the help of Fluent. The velocity
distribution shows that generation of secondary motion in the form of counter rotating vortices within the 1st half
of the diffuser. The secondary motion changes their sense of rotation after the inflexion plane of the test
diffuser. The maximum values of the mass average static Pressure recovery and total pressure loss are 36% and
13% compared to the predicted results of 39% and 11% respectively, which shows a good agreement between
the experimental and predicted results.
Design and Fabrication of Subsonic Wind TunnelIJMERJOURNAL
ABSTRACT: A Wind Tunnel is a tool used in aerodynamic research to study the effects of air moving past the solid objects. Wind tunnels were first as a means of studying vehicles (primarily airplanes) in free flight. A Wind tunnel is used to find the aerodynamics and also to measure drag and down force of airfoils. The wind tunnel is composed of a contraction cone, test section and diffuser, with nessary instrumentation to measure the drag and downforce acting on the vehicles. Our project aims at using hand fabricated wind tunnel to test aerodynamics of scaled models and also to calculate the drag in them. It is very important nowadays to consider the aerodynamics of any vehicles whiles designing, this helps in improving the efficiency and reduces the fuel consumption. With this hand fabricated wind tunnel it makes the checking of aerodynamics and calculation of drag for scaled models very easy. This reduces the time taken for designing and production
Flow Development through a Duct and a Diffuser Using CFDIJERA Editor
In the present paper an extensive study of rectangular cross-sectioned C-duct and C-diffuser is made by the help of 2-D mean velocity contours. Study of flow characteristics through constant area duct is a fundamental research area of basic fluid mechanics since the concepts of potential flow and frictional losses in conduit flow were established. C-ducts are used in aircraft intakes, combustors, internal cooling systems of gas turbines, ventilation ducts, wind tunnels etc., while diffuser is mechanical device usually made in the form of a gradual conical expander intended to raise the static pressure of the fluid flowing through it. Flow through curved ducts is more complex compared to straight duct due to the curvature of the duct axis and centrifugal forces are induced on the flowing fluid resulting in the development of secondary motion (normal to the primary flow direction) which is manifested in the form of a pair of contra-rotating vortices. For a diffuser in addition to the secondary flow, the diverging flow passage, which causes an adverse stream wise pressure gradient, can lead to flow separation. The combined effect may result n non uniformity of total pressure and total pressure loss at the exit. A comparative study of different turbulent models available in the Fluent using y as guidance in selecting the appropriate grid configuration and turbulence models are done. Standard k-ε model and RSM models are used to solve the closure problem for both the constant area duct and the diffuser. It has been observed that the Standard k-e model predicts the flow through the constant area duct and the diffuser within a reasonable domain ofthe y range.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
MATATAG CURRICULUM: ASSESSING THE READINESS OF ELEM. PUBLIC SCHOOL TEACHERS I...NelTorrente
In this research, it concludes that while the readiness of teachers in Caloocan City to implement the MATATAG Curriculum is generally positive, targeted efforts in professional development, resource distribution, support networks, and comprehensive preparation can address the existing gaps and ensure successful curriculum implementation.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Delivering Micro-Credentials in Technical and Vocational Education and TrainingAG2 Design
Explore how micro-credentials are transforming Technical and Vocational Education and Training (TVET) with this comprehensive slide deck. Discover what micro-credentials are, their importance in TVET, the advantages they offer, and the insights from industry experts. Additionally, learn about the top software applications available for creating and managing micro-credentials. This presentation also includes valuable resources and a discussion on the future of these specialised certifications.
For more detailed information on delivering micro-credentials in TVET, visit this https://tvettrainer.com/delivering-micro-credentials-in-tvet/
Study of wind effect on building with hexagonal cross section
1. THDA OF WIND EFFECT ON BUILDING WITH HEXAGONAL CROSS-SECTION
ABSTRACT
An experimental investigation of surface static pressure distributions on hexagonal
cylinder was conducted. The study was performed on the single cylinder and the group
consisting of two cylinders, one in the upstream and another in the downstream side.
The test was conducted in an open circuit wind tunnel at a Reynolds number of 4 x 10 4
based on the face width of the cylinder across the flow direction in a uniform flow of
velocity 13.5 m/s. The study was done on the single cylinder at various angles of attack
from 00 to 500 at a step of 100. The surface pressure distributions were measured with
the help of an inclined manometer. In each case the wind velocity was kept constant at
13.5 m/s. Tme velocity profile and steram line observed by using Simulation Software
FEMLAB. The pressure coefficients were calculated from the measured values of the
surface static pressure distributions on the cylinder. Then the drag and lift coefficients
were obtained from the pressure coefficients by the numerical integration method. It
was observed that the drag coefficients become remarkably smaller compared to those
for a sharp-edged square cylinder. It was also observed that at various angles of
attack, the values of the lift coefficients were insignificant compared to those for a
sharp-edged square cylinder. It can be further concluded that the hexagonal cylinder
produces significantly low values of drag and lift forces and they approach to those of
the cylinder with circular cross-section.
1. INTRODUCTION
The subject of wind load on buildings and structures is not a new one. In the 17 th
century, Galileo and Newton have considered the effect of wind loading on buildings,
but during that period, it did not gain popularity. The effect of wind loading on
buildings and structures has been considered for design purposes since late in the 19 th
century; but starting from that time up to about 1950, the studies in this field have not
been considered seriously. Buildings and their components are to be designed to
withstand the code-specified wind loads. Calculating wind loads is important in the
design of wind force-resisting system, including structural members, components, and
cladding against shear, sliding, overturning, and uplift actions.
In recent years, much emphasis has been given on “The Study of Wind Effect on
Buildings and Structures” in the different corners of the world. Even researchers in
Bangladesh have taken much interest in this field. Till now, little attention has been
paid to the flow over the bluff bodies like square cylinders, rectangular cylinders,
hexagonal cylinders etc. and some information is available concerning the flow over
them in staggered condition, although this is a problem of considerable practical
significance. With the progressing world, engineering problems regarding wind loads
Page 19 of 43
2. around a group of skyscrapers, chimneys, towers and the flow induced vibration of
tubes in heat exchangers, bridges, oil rigs or marine structures need detailed
investigation of flow patterns and aerodynamic characteristics. Arising from the
increasing practical importance of bluff body aerodynamics, over the past few decades
sufficient effort has been given in research works concerning laboratory simulations,
full-scale measurements and more recently numerical calculations and theoretical
predictions for flows over bodies of wide variety of shapes. A number of failures of
bridges, transmission towers, buildings and housings over the last one hundred years
prompted researchers to do research work in this field. The study of wind effect was
first limited to loading on buildings and structures only, possibly because of its most
dramatic effects are seen in their collapses. In mid-sixties researchers started the study
of less dramatic, but equally important environmental aspects of flow of wind around
buildings. These include the effects on pedestrians, weathering, rain penetration,
ventilation, heat loss, wind noise and air pollution etc. The pioneer researcher in this
field is Lawson T V [8] of the University of Bristol. A number of works of the
environmental aspects of wind was being studied at the Building Research
Establishment at Garson and the University of Bristol, UK.
It is true that researchers from all over the world have contributed greatly to the
knowledge of flow over bluff bodies as published by Mchuri F G et al [10] but the major
part of the reported works are of fundamental nature involving the flow over single
body of different profiles. Most of the researchers have conducted works either on
single cylinder with circular, square or rectangular section etc. or in a group with them
for various flow parameters. However, the flow over hexagonal cylinders has not been
studied extensively especially in-groups to date, although this is a problem of practical
significance. It is believed that the study on the cylinder with hexagonal section will
contribute to find the wind load on the single and group of hexagonal buildings and the
results will be useful to the relevant engineers and architects.
2. EXPERIMENTAL SETUP AND PROCEDURE
The experimental investigation to find wind load on the hexagonal cylinder was
conducted at the exit end of a wind tunnel. The schematic diagram of the experimental
setup of the present investigation has been shown in Figure 1. Open circuit subsonic
type wind tunnel was used to develop the required flow and the cylinders were
positioned at the exit end of the wind tunnel in the downstream side. The tunnel is
5.93 meter long with a test section of 460 x 480 mm cross-section. In order to make
the flow uniform a honeycomb is fixed near the end of the wind tunnel. The wind
tunnel consists of a bell-shaped converging mouth entry. A digital anemometer is used
in each of these tests to measure the wind velocity. It was the low speed wind tunnel
having the maximum wind velocity of 14 m/s in the test section. In the tunnel test
section, the measured velocity distribution was uniform.
Page 20 of 43
3. Figure 1: Schematic Diagram of Wind Tunnel
In each case of the tests, wind velocity is measured directly with the help of a digital
anemometer. The flow velocity in the test section was maintained at 13.5 m/s
approximately. The measured velocity distribution was almost uniform across the
tunnel test section in the upstream side of the test models. The pattern of the flow
velocity is shown in Figure 2 in the non-dimensional form.
Figure 2: Velocity Distribution at Upstream Side of Model Cylinder
In reality the test was done at the exit end of the wind tunnel in the open air as shown
in Figure 1. In order to fix the cylinder a steel frame was fabricated, the top floor of
which was at the same level of the wind tunnel at the exit end. Two side walls were
Page 21 of 43
4. attached to the steel frame at the two sides by the help of nut and bolt. The distance
between the extended side walls was equal to the distance of the side walls of the wind
tunnel exit end. This distance of between the side walls was 460 mm. The length of the
test section was 400 mm. There was no cover plate at the top and bottom of the
extended test section.
The cylinders were fixed with the extended sidewalls. The sidewalls were made of
plywood. In one side, the model cylinder was fastened with the side wall using nut and
bolt. The bolt was fixed with one end of the cylinder. Through the other end of the
cylinder, the plastic tubes were taken out in order to connect them with the inclined
multi-manometer. This end was supported in the groove of the sidewall of the
extended portion, compatible with the hexagonal end of the cylinder. The capillary tube
made of copper was used to make the tapping on the sides of the hexagonal model
cylinders. These copper tubes were connected with the plastic tubes. The cylinder was
leveled and then fixed very carefully so that its top and bottom sides were parallel to
the flow direction.
There was a provision for rotation of the test cylinder at various angles to obtain the
wind load at different angles of attack. Since the top and bottom of the extended part
of the wind tunnel was open; as such no correction for blockage was done in the
analysis. The test cylinders were placed very close to the end of the wind tunnel so that
the approach velocity on the test cylinders was approximately identical as that in the
exit end of the wind tunnel.
Figure 3: Taping Positions Shown on Longitudinal Section of Cylinder
In Figure 3 the taping positions on the longitudinal section of the cylinder is shown.
There were six tapings on each face of the cylinder. The distance between the
Page 22 of 43
5. consecutive taping points was equal (Δd) as shown in the figure. However, the location
of the corner taping was at a distance of ½ Δd. Each taping was identified by a
numerical number from 1 to 30 as can be seen from the figure.
Figure 4: Tunnel Test Section Showing Position of Single Cylinder
In Figure 4 the position of the single cylinder at zero angle of attack is shown in the
wind tunnel test section. In this position the top and bottom faces of the hexagonal
cylinder were parallel to the flow direction. In this position the width of the cylinder
was 50 mm in a direction perpendicular to the flow. Based on this width the Reynolds
number was calculated. The surface static pressure distributions on six faces of the
cylinder were measured in this position. Then the cylinder was rotated at an angle of
100 and the static pressure distributions on each face of the cylinder were measured
again. The same test procedure was repeated to measure the surface static pressure
distributions of the cylinders with angles of attack of 200, 300, 400 and 500.
All the data are hereby presented in terms of non-dimensional coefficients. The
coefficients of lift, drag and total force were obtained by numerical integration method.
The effect of wind on the structure as a whole is determined by the combined action of
external and internal pressures acting upon it. In all cases, the calculated wind loads
act normal to the surface to which they apply.
3. MATHEMATICAL MODEL
The calculation procedure of finding pressure coefficients, drag, lift and total force
coefficients has been described in a nutshell in this chapter. From the measured
surface static pressure on the hexagonal cylinder the pressure coefficients are
obtained.
Then the drag and lift coefficients are found from the pressure coefficients. With the
help of numerical integration method drag and lift coefficients are determined.
FEW PAGES ARE MISSING DUE TO @COPY RIGHT OF THIS ARTICLE
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6. 4. RESULTS AND DISCUSSION
5.1 Disiribuii n f Vez ciiy Fiezd:
(a) (b) (c)
Figure -6: (a) Boundry: Velocity Field, (b) Tsosurface: Velocity Field, (c) Steram line:
Velocity Field.
In Figures 6, the distributions of velocity field for angles of attack of 00 to 200 with a
step of 100 have been presented respectively.
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7. (a) (b) (c)
Figure-7: (a) Boundry: Velocity Field, (b) Tsosurface: Velocity Field, (c) Steram line:
Velocity Field.
In Figures 7, the distributions of velocity field for angles of attack of 300 to 500 with a
step of 100 have been presented respectively.
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8. 4.2 Distribution of Pressure Coefficients
The cross-section of the single hexagonal model cylinder with 30 numbers of tapings, 5
numbers on each surface of the cylinder at an angle of attack has been shown in
Figure 8. The six surfaces have been identified with S1, S2, S3, S4, S5 and S6. Pressure
coefficient for each taping point has been determined from the measured surface static
pressure.
Figure 8: Taping Positions Shown on Cross-Section of Cylinder
Figure 9: Distribution of Pressure Coefficients at Different Angles of Attack.
In Figures 9, the distributions of static pressure coefficients for angles of attack of 00 to
500 with a step of 100 have been presented respectively. While in Figure 9, the
distributions of pressure coefficients for all angles of attack have been shown for
relative comparison and Cp-distribution on the surfaces S3 to S5 is almost uniform.
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9. 4.2 Variation of Drag Coefficient
Variation of drag coefficient at various angles of attack on single hexagonal cylinder is
shown in Figure 10. The drag coefficient at different angles of attack on a single square
cylinder at uniform flow obtained by Mandal A C [8] is also presented in this figure for
comparison. It can be noticed from this figure that there is significant drop in the drag
coefficient values for the hexagonal cylinder in comparison to that of the square
cylinder and the values approaches to that of the circular cylinder. It is seen from this
figure that at zero angle of attack, the drag coefficient is about 0.95 and at all other
angles of attack, the values are close to 0.8 except at angle of attack of 100, where the
value is about 0.5. The values of the drag coefficient at various angles of attack for the
hexagonal cylinder can be explained from the Cp-distribution curves.
2.4
2.2
2
1.8
D rag C oeffic ient, C d
1.6
R ef [27]
1.4
P res ent
1.2
1
0.8
0.6
0.4
0.2
0
0 10 20 30 40 50 60
Ang le of Attack (Deg ree)
Figure 10: Variation of Drag Coefficient at Various Angles of attack on Single Cylinder
4.3 Variation of Lift Coefficient
In Figure 11 the variation of lift coefficient at various angles of attack on single
hexagonal cylinder is shown. The lift coefficient at different angles of attack on a
square cylinder at uniform flow obtained by Mandal A C [9] is also presented in this
figure for comparison. It can be noticed from this figure that the variation of the lift
coefficient on the single hexagonal cylinder is not appreciable; they are close to zero
value except at angles of attack of 100 and 500, where some insignificant values are
observed. For the single square cylinder the variation of lift coefficient with angle of
attack is remarkable. The values of the lift coefficients for the single hexagonal cylinder
can be explained from the Cp-distribution curves.
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10. 0.2
0.1
0
-0.1
L ift C oeffic ient, C l
-0.2
-0.3
-0.4
-0.5
R ef [27]
-0.6
P res ent
-0.7
-0.8
-0.9
0 10 20 30 40 50 60
Ang le of Attac t (D eg ree)
Figure 11: Variation of Lift Coefficient at Various Angles of Attack on Single Cylinder
5. CONCLUSION
The following conclusions are drawn in regard to the wind effect on the single
hexagonal cylinder and the hexagonal cylinders in a group.
a) There is significant drop in the drag coefficient values for the single hexagonal
cylinder in comparison to that of the single square cylinder and the values
approaches to that of the circular cylinder.
b) The drag coefficient for a single hexagonal cylinder at zero angle of attack is
about 0.95 in contrast to that of 2.0 for a single square cylinder at the same angle
of attack.
c) The variation of the lift coefficient on the single hexagonal cylinder is not
appreciable and they are close to zero value except at angles of attack of 100 and
500, where some insignificant values are observed.
6. REFERENCES
(1) Baines W D, “Effects of Velocity Distribution on Wind Loads and Flow Patterns
on Buildings”, Proceedings of a Symposium on Wind Effects on Buildings and
Structures”, Teddington, U.K.1963, pp.197-225.
(2) Bostock B R and Mair W A, “Pressure Distributions and Forces on Rectangular
and D-shaped Cylinders”, The Aero-dynamical Quarterly, Vol.23, 1972, pp. 499-
511.
(3) Castro J P and Fackrell J E, “A Note on Two-Dimensional Fence Flows with
Emphasis on Wall Constraint”, J. Industrial. Aerodynamics, 3(1), March 1978.
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11. (4) Davis R W and Moore E F, “A Numerical Study of Vortex Shedding from
Rectangular Cylinder,” Journal of Fluid Mechanics, Vol.116, pp.475-506.
(5) Hossain M K M, Islam M Q, Mandal A C and Saha S, “Wind Effect on Staggered
Cylinders of Square and Rectangular Sections with Variable Longitudinal
Spacing”, Transaction of the Mech. Eng. Div., The Institution of Engineers,
Bangladesh, Vol. ME38, Dec. 2007, pp. 52-57.
(6) Lawson T V, „‟Wind Loadings of Buildings, Possibilities from a Wind Tunnel
Investigation,” University of Bristol, U. K. Report on TVL/731A, August, 1975.
(7) Mchuri F G et al, “Effects of the free stream Turbulences on Drag Coefficients of
Bluff sharp – Edged Cylinders,” Nature, Vol.224. No.5222, November 29, 1969,
pp. 908-909.
(8) M. K. M. Hossain, M. Q. Islam, A. C. Mandal and S. Saha, “Wind effect on
staggered cylinders of square and Rectangular sections with variable longitudinal
spacings,” Journal of Mechanical Engineering, vol. ME38, Dec. 2007, pp-52-57.
(9) Parkinson G V and Modi V J, “Recent Research on Wind Effects on Bluff Two
Dimensional Bodies,” Proceedings, International Research Seminar, Wind Effects
on Buildings and Structures, Ottawa, Canada, 1967, pp. 485-514.
NOMENCLATURE
Symbol Meaning
A Frontal area
CD Co-efficient of Drag
CF Total force co-efficient
CL Co-efficient of Lift
CP Mean pressure co-efficient
FD Force due to drag
FL Force due to lift
∆hw Manometer reading
P Local static pressure
PO Free stream static pressure
α Angle of attack
γa Specific weight of air
γw Specific weight of manometer liquid
ρ Density of air
ρw Density of water
ΔP Difference of ambient and local static pressures.
Re Reynolds number
UO Free stream velocity
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