熱線と抵抗線群からなる新型プローブによる２成分乱流速度測定

抄録

We propose a novel probe for turbulence measurement of two velocity components. The probe is composed of a hot-wire and a group of cold-wires. The normal hot-wire placed upstream is used not only to measure an instantaneous velocity magnitude but to operate as a heat source. On the other hand, the group of cold-wires placed downstream is used to detect a thermal wake formed behind the upstream hot-wire. By applying the Gaussian interpolation technique to the cold-wire outputs to find the position of a maximum temperature rise, we can also measure an instantaneous vector of fluid velocity. The proposed technique is examined in a cylinder wake flow at x/d = 40 (Re_d ≃ 2500). The measurement results of the longitudinal and lateral rms velocities and the Reynolds shear stress are quite reasonable. It is found that a response compensation of cold-wires is indispensable for an accurate flow-direction measurement in turbulent flows.