Modeling and Analysis of Aerodynamic Bus Body using CFD

Abstract

These days it is very common in automobile industries to see many Heavy vehicles and cars(from passenger cars to sports cars) with different kinds of spoilers on them. External aerodynamics of automobiles is the key factor for vehicles overall performance. The paper presents a discussion on the results obtained from numerical simulation of air flow over a Bus body without a rear spoiler and compares these with results obtained for a Bus fitted with a rear spoiler. The influence of rear spoiler on the generated lift force and lift coefficient, velocity contours, pressure distributions and vortices generation are investigated and reported. The benchmarked modification is done by designing spoilers at the rear end for a reduced aerodynamic drag.The spoiler at the rear end is used to reduce the Lift force by creating a downward force. There will be a variation of pressure force on the different regions on the frontal side of the body due to different intensities of force acting on the bus body. In the project model, bus body is kept inside an enclosure and air is made to flow from inlet to outlet of the enclosure. The governing equation for the fluid flow were solved using CFD Expert Lite pressure based incompressible solver. CFD Expert Lite works on both Linux and Windows platforms. Steady state, three-dimensional analysis is performed for determining the Lift forces. Computation is based on the conservation equations of mass, momentum with the Standard k-epilson turbulence model. The results of the redesigned exterior body will be compared with the base model having flat roof to analyze and compare the Lift forces and coefficient of lift.