IJSRSET1844232 | Received:20March| Accepted :31March 2018 | March-April-2018[(4)4: 778-783 ] © 2018 IJSRSET | Volume 4 | Issue 4| Print ISSN: 2395-1990 | Online ISSN : 2394-4099 Themed Section: Engineering and Technology 778 CFD Analysis on Aerodynamics of an Automobile Body Deep Patel 1 , Jitendra Jangid 1 , Yash Devani 1 , Saurabh Goswami 1 , Milan Vachhani 2 1 UG Student, Mechanical Engineering Department, ITM Universe, Vadodara, Gujarat, India 2 Assistant Professor, Mechanical Engineering Department, ITM Universe, Vadodara, Gujarat, India ABSTRACT Vehicle Aerodynamics plays a crucial role and parameters such as drag as well as lift affect the performance of vehicle running at high speed. The various forces acting on a vehicle, like drag force, lift force, weight, side forces, and thrust and all these forces affect the fuel consumption rate of the car. The production of drag force and down force in automotive body are determined by analysis of air flow around it. A generic model of a sedan car and a wing type spoiler was designed in CAD software (Solid works) and performed CFD (Computational fluid dynamics) analysis on the car with and without the spoiler in the ANSYS-CFX and determined the drag coefficient and lift coefficient acting on the generic model of the sedan car. On adding the spoiler, it helps to increase the down force, which ultimately results in the stability of the vehicle and reduced fuel consumption. Keywords: CFD, Aerodynamics, Automobile body, drag coefficient, lift coefficient, ANSYS-CFX I. INTRODUCTION In today’s world, the demand of high speed cars is very huge with enhanced stability being a great concern. Aerodynamics, a branch of dynamics, is the study of the properties of air in motion and its interactions with the solid bodies. Aerodynamics is a subfield of fluid dynamics and gas dynamics and a lot of laws and theories are shared between these two branches of dynamics. The production of lift and drag forces in automotive body are determined by analysis of air flow around it. The friction between the vehicle and the air in motion around it, is called the drag force. About 60% of the total drag force is produced at the rear end of the vehicle. The automobile body in motion experiences a lift force i.e. the perpendicular component of the force exerted on the vehicle body by the oncoming flow of air. In this paper, the attempt to improve the fuel utilization by improving the aerodynamic structure of the car on adding generic model of wing type spoiler at the rear end, which helps to increase down force acting on it and ultimately increases the stability of the vehicle. A generic model of sedan car with and without spoiler, is used to determine the optimum aerodynamic Structure. SOLID WORKS is used for designing the sedan car as well as the wing type spoiler and ANSYS-CFX is used for the CFD analysis. For finding the aerodynamic drag and lift coefficient at different velocities, the analysis was performed. To obtain the air flow structure around a passenger car with a rear spoiler, this study was carried out on the numerical model based computational fluid dynamics (CFD). CFD (Computational fluid dynamics) a branch of fluid dynamics is a computational science of simulating fluid flow using computers. Steps involved in CFD analysis: 1. Geometry Definition