Numerical Investigation on Enhanced Aerodynamic Performance of a Bus using Vortex Generators - Air Tab and Shark Fin

Abstract

3D flow structures around bus models are computationally analyzed to understand the influence of vortex generator on bus body aerodynamics. The aerodynamics of a vehicle are extremely important since they influence the vehicle's overall performance. As the vehicle is moving on the road, various forces act on an automobile, such as drag and lift force, is a part of vehicle aerodynamics research. One of the primary causes of aerodynamic drag for automobiles is the flow separation at the vehicle's rear end. It is feasible to improve fuel economy by lowering the drag force. This research uses five identical bus models, four with VGs and one without. The purpose is to examine the effects of two types of vortex generators (Air-tab and Shark-fin) in terms of drag coefficient (Cd) and flow pattern developments by mounting the VGs at the rear end of the bus. The flow around the vehicle is considered to be incompressible. It is calculated using the incompressible Reynolds Navier-Stokes equations and k-ε turbulence model. Base Bus model, bus with top Shark-fin VG, bus with top Air-tab VG, bus with Shark-fin VG on 3 sides, bus with Air-tab VG on 3 sides. During the analysis, the bus is subjected to various inlet velocity ranges, ranging from 25m/s to 50 m/s, with an interval of 5m/s. The simulation results show a 7.898% reduction in coefficient of drag (Cd) from the bus model with Air tab vortex generators on 3 sides at 25 m/s.