PERFORMANCE OF A TRANSVERSE VORTICITY PROBE IN A TURBULENT CHANNEL FLOW

The performance of a four hot-wire transverse vorticity probe is teste d by comparing measurements in a fully developed turbulent channel flo w with corresponding data obtained from direct numerical simulations ( DNS) of the same flow. In the inner region, the probe performs poorly, the rms vorticities being consistently smaller than the DNS values. I n the outer region of the flow, there is reasonable agreement between measured and DNS vorticity statistics, especially after correcting the measurements for the effect of spatial resolution. In this region, th e imbalance indicated by the vorticity form of the streamwise momentum equation is approximately constant. The magnitude of the imbalance ca n be reduced to an acceptable level of accuracy by considering sources of error which affect the velocity-vorticity correlations.