FINITE-DIFFERENCE SOLUTION OF FORCED CONVECTION FROM A HOT-FILM PROBE IN A REVERSING FLOW

Abstract

A finite-difference solution of the unsteady boundary-layer equations is described for a periodically reversing flow parallel to the axis of a thin cylinder with a heated spanwise strip. The application is to the calibration of hot-film probes used for in vivo blood flow velocity measurements. The numerical results are compared with experimental and analytic results of previous investigations. The present results do not fully explain the large phase shift in heat transfer rate between theory and experiment found in a previous study. However, this phase shift is reduced in cases involving backflow. The results further indicate that inclusion of lateral diffusion and transverse curvature does not significantly affect phase as previously suggested, but that they are important factors in determining the magnitude of the heat transfer rate and hence, the magnitude of the measured velocity.