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Vortex Shedding in Bridge Engineering. Kessock Bridge Case Study. Outline. Introduction of Bridge Aeroelasticity Research Methodology Kessock Bridge Background Experimentation Computational Simulation (CFD). Introduction. Bridge Failures in the History (wind-induced instabilities)
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Vortex Shedding in Bridge Engineering Kessock Bridge Case Study
Outline • Introduction of Bridge Aeroelasticity • Research Methodology • Kessock Bridge Background • Experimentation • Computational Simulation (CFD)
Introduction • 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 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 Project Understanding the Physics of Vortex Induced Oscillation & Lock-in in Bridge Aeroelasticity
Research Methodology • Available Research Techniques • Analytical Method • Experimental Method • Computational Simulation (CFD) • Methodology • Comparison of Experimental and CFD Results; • Parametric Study via CFD;
Kessock 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)
Experimentation • 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 (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)
CFD Simulation • 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)
Mesh 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
Parametric 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;