A model for the frequency response of a near-wall hot wire: Velocity perturbation and sine-wave voltage perturbation tests

Abstract

A simplified 1-D model is developed to compute the response of a near-wall hot wire as subjected to a velocity perturbation and sine-wave voltage perturbation tests. The calculated frequency response, fD (according to the velocity perturbation test) and fbulge (according to the sine-wave perturbation test) are compared to previous experimental works, and to ascertain the relationship proposed by Teo et al. [Meas. Sci. Technol. 12 (2001) 37] between fD and fbulge. The behavioral trends of fD and fbulge are evaluated in terms of varying convection velocity, influence of wall effects and other pertinent factors. Although fD and fbulge share many similar characteristics and trends, the differences between the two responses give rise to the suggestion that while fD measures the response of heat lost from the wire in near-wall vicinity by velocity perturbation, fbulge measures the frequency response to the total heat lost from the. © 2002 Elsevier Science Inc. All rights reserved.