Vortex Shedding in Vortex Shedding in Bridge EngineeringBridge Engineering

Kessock Bridge Case Kessock Bridge Case

StudyStudy

OutlineOutline

Introduction of Bridge

Aeroelasticity

Research Methodology

Kessock Bridge Background

Experimentation

Computational Simulation

(CFD)

IntroductionIntroduction

Bridge Failures in the History (wind-induced instabilities)

Menai Strait Bridge; Bright Chain Pier; Tay Bridge (UK)

Deer Isle Bridge; Golden Gate Bridge (US)

Tacoma Narrows Bridge (Benchmark)

Classical Flutter Theory (Theodorsen)

Flight Failures (wing and wing-aileron flutter)

Langley’s Aerodome/monoplane flight failure

Fokker D-8 wing failures (1st world war)

Bridge AeroelasticityBridge Aeroelasticity

Flutter – Theories by R.H.Scanlan;

Buffeting – Theories by A.G.Davenport;

Vortex Induced Oscillation (VIO)

Lock-in Phenomenon;

Galloping;

Static Divergence;

Aim of ProjectAim of Project

Understanding the Physics of Vortex Induced Oscillation & Lock-in in Bridge Aeroelasticity

Research MethodologyResearch Methodology

Available Research Techniques

Analytical Method

Experimental Method

Computational Simulation (CFD)

MethodologyMethodology

Comparison of Experimental and CFD Results;

Parametric Study via CFD;

Kessock Bridge BackgroundKessock Bridge Background

Located in Inverness Scotland;

Encounters Relatively Strong Wind due to Local Topology

Central Span 240m;

Inverted U-shape Deck Cross-section Aerodynamically and Aeroelastically Unstable;

Full Scale Measurement (10.1991-05.1992 by Owen et.al)

Wind Tunnel Test (Dec.2003 UoN in UK & NTU in Sg)

CFD Computational Simulation (in progress)

ExperimentationExperimentation

Wind Tunnel Test

Collaborative Experiment – University of Nottingham and NangYang Technological University

1:40 Scale Sectional Model of Kessock Bridge

Force Coefficients vs. Angles of Attack

Comprehensive Full Scale Data

Verification of Experimental Data

Computational Fluid Dynamics Computational Fluid Dynamics (CFD)(CFD)

Based on Navier-Stokes Equation;

Spatial and Temporal Discretisation;

Turbulence Modelling :-

Reynolds-Averaged Navier-Stokes (RANS)

Detached Eddy Simulation (DES)

Large-Eddy Simulation (LES)

Direct Numerical Simulation (DNS)

1/40 Sectional Model – Wind Tunnel Model

SST and DES Turbulence Scheme

Fine Hexahedral Mesh (0.8m-3.7m cells)

O-Grid Construction

Non-conformal General Grid Interface (GGI)

CFD SimulationCFD Simulation

Mesh Independence TestMesh Independence Test

SST Model

Angles of Attack - ±10° (2° increment);

Lift and Drag Coefficients;

Hexahedral Meshes :-

0.8m, 1.3m and 3.7m cells;

Different Arrangement of Cell Structure;

DES for Parametric Study-10 -8 -6 -4 -2 0 2 4 6 8 10-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Angle of Attack (degree)

Lift Coeffi

cien

t

Sensitivity of Lift Coefficient at Different Angles of Attack

Wind Tunnel Test

Moving Mesh SST

O-grid SST (1.3m)

O-grid SST (0.8m)

O-grid SST (3.7m)

Parametric StudyParametric Study

DES Run :-

Finer Mesh;

Wind Speed and Direction Effects;

Varying Turbulence Intensity;

Fluid Structure Interaction;Implication of Computation Facility :-

Accuracy of Simulation;

Realisticity of Simulation;