Suppression of unsteady flow in the wake of a wall mounted dome by a localized porous substrate

Wall-mounted bluff bodies exposed to high-speed flow are common in engineering devices and aero/hydro vehicles. The wake of bluff bodies due to flow separation is highly unstable especially at high Reynolds numbers and the unsteady flow in the wake results in many adverse effects such as drag increase, structural vibration, and aero/hydro acoustic noise. While a previous experimental study has shown that a porous substrate with high permeability can suppress the flow separation behind a wall mounted obstacle in the channel, we have found that a localized porous substrate with a finite thickness can also effectively reduce flow unsteadiness in the wake. In the present study, we computationally investigate suppression of unsteady flow in the wake of wall-mounted dome by using an optimized, localized porous substrate. The flow simulations are performed by solving the volume averaged Navier-Stokes equations employing the sharp-interface immersed boundary method and the Darcy-Forchheimer model. The effects of substrate shape and permeability are investigated to find an optimal substrate configuration for the unsteady wake suppression.