Detached-Eddy Simulation and Swirl Distortion Characterization of an S-Duct Inlet

Numerical simulations were carried out to explore the flow characters and swirl distortion features of RAE M2129 S-Duct inlet using detached eddy simulation. Three freestream conditions at Mach 0.21, at angle of attack between 0 and 12 deg and at angle of sideslip between 0 and 12 deg are simulated. Results suggest that the time-averaged flow features and the aerodynamic performance of the S-Duct inlet for three freestream conditions are similar to each other; meanwhile, the time-averaged swirl distortion descriptors are also close to each other. Nevertheless, the instantaneous small-scale turbulent structures primarily induced by the freestream angle of attack lead to the generation of more strong vortices at the inlet exit plane between inlet center cone and the stbd wall, which results in larger fluctuating swirl distortions. Furthermore, the fluctuating velocity in transverse direction is more positively correlated with circumferential velocity, while the fluctuating velocity in longitude direction is more negatively correlated with circumferential velocity.