Shock-position sensitivity and performance of SBLI passive-control methods

A novel flow-control method called Smart Mesoflaps for Aeroelastic Recirculation Transpiration (SMART) can be used to control the interaction of a normal shock wave with a turbulent boundary layer by passively bleeding off low-momentum fluid downstream of the interaction and re-injecting it upstream. The SMART system is composed of a flap array that covers a cavity; the flaps undergo aeroelastic deflection when subjected to the aerodynamic loads associated with shock waves located over the cavity. Experiments were conducted to quantify the shock position sensitivity to tunnel stagnation pressure. It was found that six-flap SMART arrays make the shock position less sensitive to tunnel stagnation pressure compared to a flat plate when the shock is in its optimal running location. In contrast, a conventional porous plate does not exhibit this ability. Also presented are complementary data to those from previous research efforts that bracket the performance of four-flap SMART arrays and demonstrate that 190.5 μm four-flap arrays outperform all other SMART devices, as well as the solid-wall and conventional porous plate reference cases.