A Comparative Study of Various Diffuser Configurations on an Ahmed Body for Improved Aerodynamic Performance Using CFD

This study explores how multi-element diffusers are used in race cars and performance vehicles in order to improve cornering performance and reducing drag. Several diffuser designs are examined with a focus on lift, drag, and variations in the lift-to-drag ratio. By maximizing downforce and efficiency while minimizing overall drag and lift coefficients, this study seeks to find the optimum diffuser design on an inverted Ahmed model as a bluff body of the vehicles diffuser. After performing rigorous study on race car diffusers and understanding their functioning and configurations, a new configuration was iterated. A velocity of 60 m/s was considered as the velocity of air falling onto the Ahmed body as an average velocity after reviewing several previous research materials. The angle of inclination of the inverted Ahmed body was decided to be 15° at the rear. SOLIDWORKS 2020 was used to model the geometries, after which Ansys Fluent 2021 R2 was used for computational fluid dynamics (CFD) simulations. The base model for reference is an inverted Ahmed body with two vertical endplates attached to the rear of it. Several designs of diffusers were made and simulated on the Ahmed body, and we have finally arrived at a design which portrays significant increase in downforce compared to the 25° inclined Ahmed body with no diffuser, and the base model considered for reference. Hence, proving our point of conducting this explorative study and showing that a multi-element diffuser helps reduce drag coefficient and improves the efficiency of the body in consideration by also increasing downforce.