On the Characteristics of the Pitot-Sphere in the Flow near the Circular Pipe Wall

Abstract

The characteristics of the Pitot-sphere in the flow with a velocity gradient is different from the standard characteristics in the flow with a uniform velocity distribution. If, therefore, we measure the velocity and pressure of the flow with a velocity gradient with the Pitot-sphere using the standard cheracteristics, the results may contain some errors. To decide the errors, we experimented in the flow in the horizontal pipe approching the Pitot-sphere to the pipe wall. The results of the research may be summerized as follows : (1) The maximum error for the direction of the velocity is ±0.5°. (2) The maximum error for the magnitude of the velocity is ±4% in the range of the flow direction δ=±25°. (3) The maximum error for the pressure is 8% in the range of the flow direction δ=±25°.