Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 09, 2018 - September 12, 2018
A unique measurement technique for visualizing the spatial velocity distribution of a non-uniform flow field has been developed. By this technique which we call a “fluid velocity-field scanner (FVS),” two-dimensional velocity profiles can be obtained by tracking the path of a rod-type velocity probe with a high-speed CMOS camera, and superimposing the measurement results on the image of a measured object photographed by the same camera. The rod-type velocity probe consists of ten hot-wires operated by constant-temperature anemometer. Moving- and ensemble-average techniques are applied to the instantaneous velocity signals of the ten hot-wires to obtain the representative values on the virtual grid points for drawing a contour map of mean-velocity profile, which can be regarded as the two-dimensional time-mean velocity distribution measured by a normal hot-wire probe. Furthermore, by applying the similar moving- and ensemble-averaging to the square of the residual velocity fluctuation between the instantaneous signal and the ensemble-averaged one, turbulent intensity can also be estimated. It is demonstrated that the non-uniform distributions of mean velocity and turbulent intensity in a turbulent air jet flow can be visualized readily and quantitatively.
