Experimental investigation of the flow characteristics within a shallow wall cavity for both laminar and turbulent upstream boundary layers

The mean and turbulent flow fields were measured upstream, within, and downstream of a non-resonating shallow wall cavity subject to low Mach number flows with both laminar and turbulent upstream boundary layers. The laminar case displayed a cavity vortex that was stronger and more localized towards the trailing edge compared to the turbulent case with the same freestream velocity. The location of the maximum Reynolds shear stress in the shear layer rises slightly above the cavity mouth near the cavity centerline for the laminar case in contrast to the turbulent case, where it remains near or slightly below the cavity mouth across the entire cavity. Downstream of the cavity, the laminar and turbulent cases converged towards a common turbulent boundary layer. The non-resonating condition of the cavity was explored through comparisons with resonance criteria from previous experimental investigations.