An intuitive and comprehensive exploration of computational fluid dynamics in the study of wind engineering

Computational Fluid Dynamics for Wind Engineering provides readers with a detailed understanding of the use of computational fluid dynamics (CFD) in understanding wind loading on structures, a problem becoming more pronounced as urban density increases and buildings become larger. The work emphasizes the application of CFD to practical problems in wind loading and helps readers understand important associated factors such as turbulent flow around buildings and bridges.

Written by a highly qualified professor with extensive research experience in related fields, the book includes accessible summaries at the end of each chapter. Every chapter also offers relevant and engaging practice material to help students learn and retain the concepts discussed within, and the use of the OpenFOAM tool—an open-source wind engineering application—is explored as well.

Computational Fluid Dynamics for Wind Engineering covers topics like:

• Fluid mechanics, turbulence in fluid mechanics, turbulence modelling, and mathematical modelling of wind engineering problems
• The finite difference method for CFD, solutions to the incompressible Navier-Stokes equations, visualization, and animation in CFD, and the application of CFD to building and bridge aerodynamics
• How to compare CFD analysis with wind tunnel measurements, field measurements, and the ASCE-7 pressure coefficients
• Wind effects and strain on large structures

Providing comprehensive coverage of how CFD can explain wind load on structures and helpful examples of practical applications, Computational Fluid Dynamics for Wind Engineering serves as an invaluable resource for senior undergraduate students, graduate students, and researchers and practitioners of civil and structural engineering.

Panneer Selvam is University Professor and holds the James T. Womble Endowed Professorship in Computational Mechanics and Nanotechnology Modelling in the Department of Civil Engineering at the University of Arkansas. His research interests include structural analysis, structural loading, finite element methods in civil engineering, numerical modelling of linear, nonlinear, and dynamic behaviour in structural mechanics, and fluid dynamics and acoustics using boundary element, finite element, and finite difference methods. He is also interested in computer modeling in wind engineering, understanding turbulent flow, thermal energy storage, thermal management for electronics, and fluid-structure interaction problems.

Preface

1 Introduction

1.1 Brief Review of Steps in CFD Modeling

1.2 CFD for Wind Engineering

2 Introduction to Fluid Mechanics

2.1 Navier-Stokes Equations

2.2 Governing Equations for Compressible Newtonian Flow

2.3 Definition of Convection and Diffusion

2.4 Derivation of Bernoulli Equations

2.5 Velocity Computation in an Incompressible, Irrotational, Steady and Inviscid Flow

2.6 Non-dimensional NS Equations

2.7 Properties of Fluids

2.7.1 Properties of Air

2.7.2 Change in Velocity to Change in Energy

2.7.3 Change in Temperature to Change in Energy

2.8 Solution of Linear and Nonlinear Equations

2.9 Laminar and Turbulence Flow

2.10 Velocity Spectrum & Spectrum Considered by Different Turbulence Models

2.11 Turbulence Modeling

2.12 Law of the Wall

2.13 Boundary Layer Depth Estimation

2.14 Chapter Outcome

Problems

References

3 Finite Difference Method

3.1 Introduction to Finite Difference Method

3.2 Example for 2D Potential Problem and Solution of Simultaneous Equations-Direct & Iterative Methods

3.3 Finite Difference Method of Approximating the Partial Differential Equation

3.3.1 Introduction to Finite Difference Method

3.3.2 Physical Problem and Modeling

3.3.3 Direct Method of Solution

3.3.4 Memory Requirements for a 100x100 Mesh

3.3.5 Iterative Method by Gauss-Siedel (GS) or Successive Over Relaxation (SOR)

3.3.6 Details of Program Pcham.f

3.3.7 Optimum Relaxation Parameter RF for SOR

3.3.8 Inviscid Flow Over a Square Cylinder or Building

3.3.9 Iterative Solvers Used in Practical Applications

3.4 Unsteady Problem-Explicit and Implicit Solution for the Wave Equation

3.4.1 Discretization of the Wave Equation by Different FDM Schemes

3.4.2 Input Preparation

3.4.3 Information Needed to Solve Unsteady Problems

3.5 Solution of the Incompressible Navier-Stokes (NS) Equations

3.6 Storage of Variables in Staggered and Non-Staggered Grid Systems

3.7 Node and Cell-Centered Storage Locations

3.8 Structured and Unstructured Grid Systems

3.9 Variable Storage Methods

3.10 Practical Comments for Solving the NS equation

3.11 Chapter Outcome

Problems

References

4 Introduction to Wind Engineering

4.1 Wind Velocity Profile Due to Ground Roughness and Height

4.1.1 Wind Velocity with Height

4.2 Topographic Effect on Wind Speed

4.3 Wind Speed and Wind Pressure

4.4 Wind and Structure Interaction

4.4.1 Shape effect

4.4.2 Structural Dynamic Effect in the Along Wind Direction

4.4.3 Structural Dynamic Effect in the Across Wind Direction

4.5 Opening in the Building

4.6 Phenomena not Considered by the ASCE 7-16

4.7 ASCE 7-16 on Method of Calculating Wind Load

Problems

References

5 CFD for Turbulent Flow

5.1 Mean and Peak Pressure Coefficients from ASCE 7-16 and Need for CFD

5.2 Procedure for CFD Modeling

5.3 Need for Non-dimensional Flow Modeling

5.4 Flow Over 2D Building & Flow Over an Escarpment

5.5 Pressure on the Texas Tech University (TTU) Building Without Inflow Turbulence

5.5.1 Mathematical & Numerical Modeling

5.5.2 Detail of the TTU Building and the Computational Region

5.5.3 Grid Generation

5.5.4 Time Step and Total Time to Run

5.5.5 Details of Program yif2.f

5.5.6 Files Needed to Run the Program

5.5.7 Input Data File-yif-i.txt

5.5.8 Output Detail

5.5.9 Screen-Writing

5.5.10 File Detail: yif-o.plt

5.5.11 File Detail: yif-o2.plt

5.5.12 File Detail: yif-o3.plt

5.5.13 File Detail: yif-p.plt

5.5.14 File Detail: prcon.plt

5.6 Unsteady Flow over Building

5.6.1 Pressure on the TTU Building with Inflow Turbulence

5.6.2 Inflow Turbulence Generation Methods

5.6.3 Inflow Turbulence Effect on Flow and Pressure without Building

5.6.4 Computation of Wind Spectrum Using the Program yif2.f

5.6.5 Peak Pressure on TTU Building Using Inflow Turbulence

5.7 Flow Around a Cylinder and Practical Relevance to Bridge Aerodynamics

5.8 Chapter Outcome

Problems

References

6 Advanced Topics

6.1 Grid Generation for Practical Applications

6.1.1 Flow Around Complex Building and Bridge Shapes

6.2 Structural Aeroelasticity and Structural Dynamics

6.2.1 Fluid Structure Interaction (FSI) Methods

6.2.2 Moving Grid for FSI Computation

6.2.3 Vortex Shedding

6.2.4 Galloping of a Rectangular Cylinder

6.2.5 Bridge Aerodynamics

6.2.5.1 Fixed Bridge Computation

6.2.5.2 Movable Bridge Computation for Critical Flutter Velocity Using Moving Bridge

6.2.5.3 Estimation of Negative Damping Coefficient of a Bridge Considering the Response as a Free Vibration

6.3 Inflow Turbulence by Body Forcing

6.4 CFD for Improving Wind Turbine Performance and Siting and Wind Tunnel Design

6.4.1 Actuator Disc Method (ADM)

6.4.2 Actuator Line Method (ALM)

6.4.3 Multiple Reference Frame

6.4.4 Sliding Mesh Model or Rigid Body Motion Model

6.4.5 Wind Tunnel Flow Modeling and Design

6.4.6 Improving Wind Turbine Performance

6.5 Tornado-Structure Interaction

6.5.1 Tornado Models for Engineering Applications

6.5.2 Analytical Vortex Model

6.5.3 Vortex Generation Chamber Models

6.5.3.1 Stationary Vortex Chamber

6.5.3.2 Moving Vortex Chamber

6.6 Wind Environment Around Buildings

6.7 Pollutant Transport Around Buildings

6.8 Parallel Computing for Wind Engineering

6.9 Chapter Outcome

Problems

References

7 Introduction to OpenFOAM Application to Wind Engineering

7.1 Introduction to OpenFOAM and ParaView for Wind Engineering

7.1.1 OpenFOAM for Wind Engineering

7.1.2 Grid Generation

7.1.3 Visualization

7.2 Installation of OpenFOAM, ParaView and Running a Sample File

7.2.1 Installation of OpenFOAM and ParaView

7.2.2 Running a Problem Using OpenFOAM

7.3 CFD Solvers and Explanation of Input File for Flow Around a Cube

7.3.1 Numerical Schemes and Solvers for the NS equation

7.3.2 Flow Around a Cube Using Uniform Inflow

7.3.3 Detail of ‘constant’ Directory

7.3.4 Detail of ‘0’ Directory

7.3.5 Grid Generation Using blockMesh

7.3.6 Detail of ‘fvSchemes’ File

7.3.7 Detail of ‘fvSolution’ File

7.3.8 Detail of ‘controlDict’ File

7.3.9 Time Variation of Data

7.3.10 Space Data Retrieval from ParaView

7.4 Visualization Using ParaView

7.5 Analysis of Flow Over Cube Data for Uniform Flow at the Inlet

7.6 Computation of Turbulent Flow Over a Cube

7.6.1 Detail of ‘constant’ Directory

7.6.2 Detail of ‘system’ Directory

7.6.3 Inflow Details

7.7 Multilevel Mesh Resolution Using snappyHexMesh Mesh Generator in OpenFOAM

7.8 Challenges in Using OpenFOAM

7.9 Summary and Conclusions

7.10 Chapter Outcome

Problems

References

Appendices

A.1  Tecplot for Visualization

A.2 Random Process for Wind Engineering

 References

A.3 Direct Solution of Ax=b by A-1