Minimization of divergence error in volumetric velocity measurements and implications for turbulence statistics

Abstract

Volumetric velocity measurements taken in incompressible fluids are typically hindered by a nonzero divergence error due to experimental uncertainties. Here, we present a technique to minimize divergence error by employing continuity of mass as a constraint, with minimal change to the measured velocity field. The divergence correction scheme (DCS) is implemented using a constraint-based nonlinear optimization. An assessment of DCS is performed using direct numerical simulations (DNS) velocity fields with random noise added to emulate experimental uncertainties, together with a Tomographic particle image velocimetry data set measured in a channel flow facility at a matched Reynolds number to ..