CFD Analysis of Slipstreaming and Side Drafting Techniques Concerning Aerodynamic Drag in NASCAR Racing

Abstract

NASCAR has given enormous concentration on aerodynamics in racing in which drivers

rely solely on aerodynamic techniques in pursuit of podium finishes. Since drag

accounts for roughly 90% total resistance at top speed, NASCAR drivers have resorted

to such techniques in gaining aerodynamic advantages. Presently, there are little in

depth investigations found on slipstreaming in applications of high-speed NASCAR race

cars and even lesser to none on side drafting. The effects of slipstreaming were studied

by varying the vehicle spacing and platoon population of platoon members, whereas

the effects of side drafting were studied by varying the longitudinal position and lateral

separation between trailing and leading vehicles. The results prove that slipstreaming

is beneficial to platoon members in significantly reducing aerodynamic drag at short

vehicle spacings. However, there exists a ‘drag bubble’ within specific ranges of vehicle

spacing where trailing vehicles experience significant drag increments. Increasing the

platoon population is found to decrease the average drag values of platoon members

to a certain extent. On the other hand, the side drafting study reveals that the leading

car undergoes significant drag increments while the trailing car experiences some drag

reduction, thus proving substantial aerodynamic advantages for trailing vehicles in

raising their overtaking capabilities.