A simple three component velocity measurement method using a rotated split-film sensor

A rotated split-film anemometry method which can be used to obtain three-component average flow velocities is reviewed and evaluated. The related theory, apparatus, calibration procedure, and results of the new technique are discussed. The new technique utilizes a single split-film probe in combination with a mechanical rotating probe, holder. The basic procedure is to make a plane or two-component velocity measurement with the probe in one orientation and then to rotate the probe 90° and make another measurement. The two pairs of velocity and flow angle data, are correlated, for yawed flow effects, and resolved to identify three (steady-flow) speed and direction components. Measurements in an axisymmetric jet at various flow speeds and angles indicate that the method has, under most circumstances, errors of about 5%. Slightly greater errors were encountered at extreme test flow speeds and at large sensor yaw and pitch angles