LAUSR

Abstract An investigation on the modification of turbulent boundary layer characteristics by wall heating was conducted on the mixed convection turbulent boundary layer flow. The multi-plane particle image velocimetry (PIV) technique was used to characterize turbulent boundary layer dynamics. Experiments were performed over a range of mixed convection flow conditions, quantified by the Richardson number ( Ri ), from inertia dominant flow ( R i L = 0.01 ) to buoyancy-influenced flow ( R i L = 0.3 ). The implemented PIV technique produced multiple two-dimensional velocity fields from two orthogonal planes with respect to the mean-flow direction. From the computed velocity fields, the low-order turbulent statistics were computed where a significant modification to the wall normal stress was observed. The cause of this modification was investigated via the probability density function (PDF) of the turbulent wall-normal velocity component ( v ' ). Results show that the PDF of v ' is multi-modal in the presence of wall heating, demonstrating that the buoyancy-driven phenomena influence the turbulent boundary layer flow via intermittent bursting and rising of thermals through the boundary layer.