Simultaneous measurement of all three velocity components and pressure in a plane jet

Abstract

Simultaneous measurement of all three velocity components and static pressure in a plane turbulent jet is performed by developing a new probe for the measurement. The combined probe consists of two X-type hot-wire sensors and a static pressure tube placed at the center of hot-wires. The static pressure tube is miniaturized with a micro electromechanical system fabrication technique to improve spatial resolution. The results of the calibration test show that the measurement accuracy of the pressure fluctuation with the pressure tube is 9%. Further, we are able to compensate for the cross-flow error of the pressure tube by instantaneously measuring all the velocity components with two X-type hot-wire sensors. The profile of the production term and diffusion term in the turbulent energy transport equation, directly estimated with the measured data, also shows slight improvement compared to our previous studies. This is due to the improvement in the spatial resolution of the combined probe and the improvement in the measurement accuracy of both the velocity-kinematic energy correlation and that of the velocity–pressure correlation by measuring all velocity components. Further, it is also found that the pressure diffusion of the turbulent energy in the plane jet is mainly caused due to the fluctuation whose frequency is from 20 to 40 Hz, which corresponds to the flapping frequency in the present experiment condition.