Development and testing of pulsed-wire probes for measuring fluctuating quantities in highly turbulent flows

The pulsed wire anemometer is one of the few devices allowing measurements in flows with instantaneous flow reversal and high turbulence levels. Calculations of the measurement error due to a limited acceptance cone, however, predicted a behaviour of this error in some cases contrary to what the experimental results in turbulent shear flows showed. Pulsed-wire probes were built and tested to estimate the size of their acceptance cones. Within the acceptance cones a "critical region" was discovered in which the velocity samples still reached the sensor wires but were severely altered by the wake of one of the prongs. Measurements were performed in two highly turbulent shear flows in order to estimate at least the order of magnitude of the errors. Within some of the data a considerable scatter occurred, caused to a large degree by differences in the size and the symmetry of both the acceptance cones and the critical regions and in differences in the quality of approximating the calibration curve of the sensors used. The differences between data taken with the "best" sensor and theX-wire measurements including error estimates is less than 7% in the measurements of $$\sqrt {\overline {r\prime ^2 } } $$ and $$\overline {u\prime v\prime } $$ .