CFD Aerodynamic Analysis of Ahmed Body

Abstract — The CFD (Computational Fluid Dynamics) analysis is used to find the parameter in the automobile industry. This analysis is used to understand the fuel consumption, stability of the vehicle and passenger comfort. The air flow over ground vehicle is analysed and coefficient of drag is calculated using CFD (Ansys Fluent). For this calculation, Ahmed body (simplified car body) as ground vehicle is considered which is commonly used as test case in industry. The Ahmed body is made up of a round front part, a movable slant plane placed in the rear of the body to study the separation phenomena at 250, 350 angles, and a rectangular box, which connects the front and rear slant plane. The most significant feature of the body is the 250, 350 angle of rear slant. Air is used as a working fluid. The inlet velocity of fluid is 40 m/s. k-ε turbulent model used as a standard model. Two separate cases have been solved for two different front radius of Ahmed body R80, R120 and ground clearance at 20mm, 40mm and results are comparing. The results are present in the form of drag coefficient value and flow field which include velocity contour and velocity vector fields. the validation is carried out by simulation around the Ahmed body with the rear slant angle of 250,350.the actual wind tunnel experimental data are compared with the results