Probe Blockage Effects in Free Jets and Closed Tunnels
1975 ◽
Vol 97
(4)
◽
pp. 509-514
◽
Keyword(s):
The effect of probe blockage on the free-stream pressure and Mach number has been studied for the two limiting cases of open free jets and closed tunnels. Cylinder probe calibrations carried out in subsonic free jets show that the blockage effect is much greater than previous analytical solutions predict. The blockage effect in free jets was found to be of approximately the same magnitude as in closed tunnels. Generalized blockage corrections are derived which indicate the importance of minimizing blockage effects both when calibrating a probe and when using it to make pressure measurements, especially in the transonic flow regime.