Wall Friction and Local Heat Transfer in Oscillatory Flow : Two-dimensional Unsteady Laminar Boundary Layer on a Flat Plate

Abstract

Wall friction and local heat transfer in an oscillating laminar boundary layer over a flat plate with an unheated starting length are theoretically analyzed. In the analysis, the power series solutions are derived for velocity and temperature distributions in three frequency regions, that is, low frequency (ω*<1), intermediate frequency (1<ω*<1/K), response of a hot film sensor is clarified theoretically. Especially it is shown that the amplitude of heat transfer oscillation with an unheated starting length increase with frequency at low and intermediate regions, and the phase angle is in advance of free stream oscillation at these frequency regions.