Computational Study of Asymmetric Gaps
Thiago F. Rezende, Felipe Oliveira Aguirre, Victor Barcelos Victorino, Marcello Augusto Faraco de Medeiros · 2024
The transition of the boundary layer in fluid flows has significant implications for the aerodynamic drag imposed on air transportation vehicles due to the high coefficient of friction of the turbulent boundary layer. The presence of small rectangular cavities on the surface of the vehicle can induce the transition. Flow stability analyses over cavities demonstrate that the interaction between two-dimensional Rossiter modes and three-dimensional centrifugal modes plays a crucial role in the boundary layer transition process. In this work, we numerically evaluate the stability of compressible flows over asymmetric rectangular cavities, meaning cavities with different heights at the trailing edge compared to the leading edge. We apply two-dimensional and three-dimensional direct numerical simulations of the compressible Navier-Stokes equations and linear stability theory using high-fidelity algorithms. The analyses suggest that increases in the height of the trailing edge enhance the stability of both two-dimensional and three-dimensional modes, while lower trailing edges significantly increase the temporal amplification rate of dominant modes. Ultimately, the results suggest that reductions in the height of the trailing edge of a cavity may accelerate boundary layer transition, while increases in trailing edge height may delay it.