Simulating particle inertia for velocimetry measurements of a flow behind an expanding shock wave

Abstract

When particle-based velocimetry techniques are applied to complex high-speed flows, the non-ideal tracing capability of seeding particles becomes most prominent. Here, we present a numerical particle tracking methodology to predict the bias errors associated with particle image velocimetry (PIV) of flows with moving shocks. The methodology involves performing computational fluid dynamics simulations that yield time-varying flow fields, which are then used to compute the actual paths and velocities of the seeding particles. We test this approach on PIV measurements of the velocity field behind an expanding semi-cylindrical shock wave, generated by a pulsed sliding discharge. Although in transient high-speed compressible flows the PIV imaging accuracy is still hindered by the finite particle response, the proposed methodology allows for both a successful quantification of PIV errors as well as a direct comparison between particle-based velocimetry and numerical simulations.