Vorticity meter calibration using a cross-wires survey

Abstract

A vorticity meter of the vane-type has been used in this study for direct and quantitative measurements of vertical flows. The vane calibration procedure is carried out by using measurements deduced from a preliminary cross-wires survey of the flow-field generated in the wake of a half wing set at incidence in the wind tunnel. Emphasis is placed on the resulting calibration law which relates the vane rotational speed to the fluid angular velocity. Specially it is shown that this calibration law can be obtained as a linear expression by taking into account the minimum threshold rotational speed necessary for vane rotation. When comparing vorticity distributions obtained through the vortical wing wake by the indirect cross-wires technique, good agreements are found with the corresponding vorticity distributions as deduced from the so calibrated vorticity meter.