Computational Fluid Dynamics for Civil Engineering Infrastructure

Abstract

The research has three main objectives. The first objective is to develop the theoretical background of CFD. The second objective is to compare the result of wind fatigue design load on cantilever sign support structure specifically for natural wind gust using computational fluid dynamics (CFD) with the result from the AASHTO provision which is derived by considering the yearly mean wind speed. The final objective is to show the application of CFD in civil engineering. The study came up with the following conclusion. The bending stress at the critical locations i.e. at the base and at the connection between the horizontal and vertical member are considered to compare the result of AASHTO provision to that of CFD analysis. The results shows that the bending stress from AASHTO provision is much greater than the bending stress form the CFD analysis. This is because AASHTO considers a yearly mean wind speed where as the CFD analysis take into consideration a onetime natural wind gust. After running the model for different wind velocity, it is found that the pressure on the structure for 22.35m/s (50mph) wind gust in ANSYS-CFX gives approximately equal value of stress with the value of the wind gust pressure calculated using AASHTO provision for a yearly mean wind speed of 5m/s (11.2mph).