Turbulence Measurements at Low Velocities with Symmetrically Bent V-Shaped Hot-Wires : 1st Report, Heat Transfer Characteristics

Abstract

The heat transfer characteristics of a V-shaped hot-wire, which was originally developed for reliable measurements of near-wall turbulence, are investigated for measurements of small gas velocities. The effective cooling velocity of a V-shaped hot-wire can be represented by the relation U²_e= U²_n+k²U²_t1+h²U²_t2 for the fluid velocity range 0.05 to 1.0m/s, where U_n, U_t1 and U_t2 are the orthogonal velocity components in the hot-wire oriented coordinate system. For a given type of wire, the sensitivity coefficients, k and h, are dependent primarily upon the fluid velocity and almost independent of the wire orientation. The effect of the wire configuration on heat transfer characteristics is shown and discussed.