Dissipation rate estimation in the turbulent boundary layer using high-speed planar particle image velocimetry

Abstract

The challenge of turbulent kinetic energy dissipation rate estimation, in general, is associated with errors embedded in measured velocity vectors and spatial resolution of appropriate optical method. Different optical methods together with different filtering procedures may yield completely different estimations. To evaluate the sources for such discrepancies, key parameters and factors which directly affect the accuracy of the dissipation rate estimation are briefly discussed. A joint effect of random error, velocity vector spacing, IW size and IW overlap on the dissipation rate estimation is theoretically and experimentally shown. In the present study, we demonstrate that high-speed planar particle image velocimetry (PIV) enables accurate estimation of the dissipation rate if high spatiotemporal resolution and appropriate local temporal filtering procedure are utilized. We consider a synthetic linear shear flow and a turbulent boundary layer flow using an assumption of locally axisymmetric turbulence when estimating the dissipation rate. The calculated dissipation rate profiles are compared with measurements by the state-of-the-art optical methods such as planar smoke image velocimetry (SIV), Stereo PIV, Tomo PIV, Tomo PTV–VIC+, and DNS results. The advantages of the implemented technique compared to others and the temporal filtering procedure are discussed.