The application of PIV (Particle Image Velocimetry) to transonic flow measurements

A number of PIV (Particle Image Velocity) measurements have been made at transonic speeds. The initial objective of the work has been to explore if such measurements could be made remotely and processed in an accurate and automatic fashion. Subsequently PIV measurements have been made remotely at optical stand-off distance of up to 1 m. PIV results are presented, made at ARA Bedford on a 1/12th scale model of an Airbus wing, where a separation induced shock has been measured in three dimensions. The paper also presents results achieved using PIV at DRA Pyestock in mapping the flow within a full size annular turbine cascade with a velocity measurement accuracy of 1%. Measurements are presented showing the wake measured downstream of an annular turbine stator row. The measurements clearly show the presence of a vortex street which has a width of approximately 3 mm.