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 ($\mathit{Ri}$), 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 ($v\text{'}$). Results show that the PDF of $v\text{'}$ 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.

对混合对流湍流边界层流动进行了壁面加热对湍流边界层特性的修正研究。多平面粒子图像测速 (PIV) 技术用于表征湍流边界层动力学。实验是在一系列混合对流条件下进行的，由理查森数（$\mathit{里}$), 从惯性主导流 ($\mathrm{电阻}{\mathrm{一世}}_{升}=0.01$) 到受浮力影响的流动 ($\mathrm{电阻}{\mathrm{一世}}_{升}=0.3$）。实施的 PIV 技术从相对于平均流方向的两个正交平面产生多个二维速度场。根据计算出的速度场，计算低阶湍流统计数据，其中观察到壁法向应力的显着修改。通过湍流壁法向速度分量的概率密度函数 (PDF) 调查了这种修改的原因 ($v\text{'}$）。结果表明，PDF$v\text{'}$ 在壁面加热的情况下是多模态的，表明浮力驱动的现象通过间歇性爆裂和通过边界层的热气流上升来影响湍流边界层流动。