On the measurement of lateral velocity derivatives in turbulent flows

Abstract

Direct numerical simulation data for the lateral velocity derivative ∂u/∂y at the centreline of a fully developed turbulent channel flow provide reasonable support for Wyngaard's analysis of the error involved in measuring this quantity using parallel hot wires. Numerical data in the wall region of the channel flow also provide a useful indication of how to select the separation between the wires. Justification for this choice is obtained by comparing several measured statistics of ∂u/∂y with the corresponding numerical data.