An Omni-Directional Static Pressure Probe

Abstract

A rugged field experiment version of the double-disk static pressure probe is described. The probe consists of two circular disks placed one over the other. Static pressure is sensed through two mutually facing sensing ports located in the center of each disk. Static pressure errors induced by air flow curvature over the leading edges of the disks are minimized through the introduction of shallow dimples centered about the sensing ports. Optimal angle-of-attack performance is obtained by varying the spacing between the disks. Wind tunnel tests were performed to determine the respective influence of disk thickness, dimple geometry and disk separation distance on the response of the probe to vertical and horizontal variations in wind direction and speed. The results show that the introduction of sensing port dimples on reasonably thick plate probes can reduce curvature-induced errors to less than 1% of the dynamic velocity head, and that angle-of-attack errors can be kept to ±0.5% over ±14° variations in wind direction.