The characteristics of a cylindrical probe at high subsonic speeds. part 1. The case of zero inclination angle

In using the probe to measure the direction and the speed of high subsonic internal flows which are observed in high speed turbomachines such as transonic or supersonic compressors, the characteristics of the probe must be known beforehand. As a first step, the characteristics of a cylindrical probe at high subsonic speeds were investigated in the case of zero inclination angle. The experiments were carried out over a range of flow Mach numbers from 0.3 to 0.79. Yaw angles were varied from -20° to +20°. Both the direction and the total pressure coefficients obtained were independent of Mach numbers. Hence, in the practical application of the probe as a yawmeter, the direction of wind velocity and the total pressure can be obtained directly from simple calibration curves. Although the static pressure coefficient obtained was a function of Mach number, a simple relation was observed within yaw angles of ±10°, and the static pressure and the Mach number can be easily obtained in this range by the successive approximation method.