Performance of a three-component vorticity probe in a turbulent far-wake

A new four X-wire vorticity probe has been developed to measure all three c omponents of the vorticity fluctuation vector simultaneously. The performan ce of this probe is tested in a turbulent far-wake. The measured Reynolds s tresses agree with those obtained previously from simpler hot wire configur ations. The variances of the lateral vorticity components agree within +/-1 5% with those measured with a one-component vorticity probe. The variances of the streamwise vorticity component are also in reasonable agreement with those inferred from two X-wires. At high wavenumbers, the measured vortici ty spectra agree with those obtained by direct numerical simulation (DNS) i n the central region of a turbulent channel flow. The comparison of measure d high-order moments of vorticity on the wake centerline with local isotrop y also suggests the probe performs satisfactorily.