An experimental study of a turbulent boundary layer with favorable and adverse pressure gradients*

A turbulent boundary layer is studied as it undergoes a favorable and adverse pressure gradient in sequence. A deformable ceiling panel is used (Parthasarathy & Saxton-Fox, 2022) to apply a range of pressure gradients on the boundary layer. This talk will focus on the turbulent statistics and structures within statically held but non-equilibrium pressure gradients. Planar PIV (particle image velocimetry) and preliminary stereo PIV data at will be reported. This data is collected using a mobile particle image velocimetry rig, which allows for 2100 mm of adjustment in the streamwise direction and 200 mm of adjustment in the spanwise direction. This was built to enable rapid data collection in the multiple fields of view with high degree of repeatability. The stereo PIV data will be reported from two planes: one in the favorable pressure gradient and one in the adverse pressure gradient region. The talk will also highlight the long-term plans to acquire data upstream of the pressure gradient imposition and at the side walls of the wind tunnel, to enable careful comparison with computation. This data will be compiled into a publicly available database for use in further research.