Analysis of the aerodynamics of a public transportation vehicle using CFD

Abstract

The main purpose of this study was to develop the aerodynamic study of a Maharashtra state
road transport bus. The rising fuel price and strict government regulations makes the road transport
uneconomical now days. With the objective of increasing fuel efficiency and reducing the emission of
harmful exhaust gases. It has been proven experimentally that vehicle consumes almost 40% of the
available useful engine power to overcome the drag resistance. This provides us a huge scope to study the
influence of aerodynamic drag. The initial of the project was to identify the drag coefficient of the
existing ordinary type model called “Parivartan” from ANSYS fluent. After preliminary analysis of the
existing model corresponding changes are made in such a way that their implementation should be
possible at workshop level. The simulation of the air flow over the bus was performed in two steps:
design on SolidWorks CAD and ANSYS (FLUENT) is used as a virtual analysis tool to estimate the drag
coefficient of the bus. We have used the turbulence models k-ε Realizable having a better approximation
of the actual result. Around 28% improvement in the drag coefficient is achieved by CFD driven changes
in the bus design. Coefficient of drag is improved by 28 % and fuel efficiency increased by 20% by CFD
driven changes.c