Investigation on error correction method of five-holes probes used in flow field with large velocity gradient

In order to explore the distortion characteristics of the five-holes probe under a large gradient flow field (Δv/v), a data processing method for correcting the measurement error caused by the velocity gradient is established. An investigation based on the five-holes probe principle is employed to reveal the effect of the flow angle and velocity gradient on the measurement error. A correct method is proposed and verified by the experiment. The results show: the measurement error of the velocity value is far less than that of the flow angle and can be ignored in ordinary range (Δv/v ranges from –0.3 to 0.3 in this paper). The measurement error of the flow angle is usually notable. The error is affected by the velocity gradient and flow angle. The results of the experiment confirm that the correction method based on the velocity gradient and flow angle can reduce the angle error effectively.