Tomographic Particle Image Velocimetry Measurements of a High Reynolds Number Turbulent Boundary Layer*

Streamwise/wall-parallel volumes in the buffer region of a turbulent boundary layer at Re$_{\theta }$ =7800 and 11800 are measured using a 4 camera (2048 $\times $ 2048 px) tomographic particle image velocimetry (Tomo-PIV) system in the turbulent boundary layer wind tunnel at the Laboratoire de M\'{e}canique de Lille (LML). Measurement volumes of 1200 $\times $ 180 $\times $ 1200 pixels are achieved, the large boundary layer provided by this tunnel ($\delta \sim $ 0.3 m) resulting in volumes of 470$^{+} \times $ 70$^{+} \times $ 470$^{+}$ and 920$^{+} \times $ 140$^{+} \times $ 920$^{+}$ wall units, respectively. The quality of the data acquired by this technique is assessed based on the mean velocity profile, velocity fluctuations, velocity power spectrum and the fluctuating divergence. Streaks and streamwise vortices are examined and an attempt is made to classify the flow using the invariants of the full velocity gradient tensor.