平行二線式熱線流速計による壁面せん断乱流における2方向速度変動計測の高精度化への試み

抄録

In the present study, we have developed a two-dimensional velocity vector sensor using two identical hot-wires placed close together and parallel to each other. To clarify the principle of operation of the sensor, we have used the OpenFOAM software and performed numerical analysis of the velocity field around the sensor consisting of the two hot-wires. As a result, it is shown that the thermal boundary layers developing from the close vicinity of each hot-wire can induce the thermal interference between the hot-wire measurements. Thus, a wall-normal velocity component existing in wall turbulent shear flows will affect the output of each hot-wire of the sensor. In the present study, measurement accuracy of the two component velocity fluctuations obtained by the proposed sensor is appraised experimentally using a canonical flat-plate turbulent boundary layer. Then, it was verified that the present velocity sensor can reproduce not only the DNS results but also the experimental ones measured by the standard I- and/or X-type hot-wire probes. A notable advantage of the proposed hot-wire sensor should be that it can be brought closer to the wall than the X-type one.