Motivated by the inclusion of active flow control provisions in the 2026 Formula
One regulations, and building upon previous studies of Trapped Vortex Cavity
(TVC) implementation in inverted front wings, this paper investigates the
effectiveness of TVC as a flow control mechanism applied to vehicle diffusers.
Both active and passive configurations were considered for three diffuser
geometries: a base straight-line diffuser, an inverted airfoil-shaped diffuser,
and a diffuser inspired by a Formula One car. The study employed numerical
simulations to evaluate the aerodynamic performance and the potential benefits
of integrating TVC systems. Across all types of diffusers, the implementation of
a circular TVC cavity resulted in a significant improvement in the lift-to-drag
ratio (CL/CD). In the active flow control configuration, a 10% improvement was
observed in the straight diffuser under a limited mass-flow rate. With optimized
cavity positioning and radius, the airfoil-shaped and Formula One-inspired
diffusers achieved improvements of 38.9% and 54.6%, respectively, under the same
flow conditions. Passive flow control also demonstrated notable aerodynamic
benefits without additional energy input. Compared to the original diffuser
configurations, performance gains of 8%, 23.6%, and 12.9% were recorded for the
straight, airfoil-shaped, and Formula One-inspired diffusers, respectively. The
results suggest that the integration of a TVC system in the diffuser could
effectively enhance aerodynamic performance by strengthening suction effects and
promoting secondary pressure recovery, regardless of diffuser geometry.