抄録
The frequency response of transfer coefficient to flow-rate change in laminar tube flow is studied experimentally and analytically. In the analysis, the linearized basic equation is solved both numerically and by using a similarity variable which is used in analysis of steady-state problem. In the experiment, the variations of local value and space-averaged value with respect to time are measured under two heating conditions, i.e., constant wall heat-flux and constant wall temperature.
From these results it is concluded that the similarity relation is not preserved in unsteady state and that resonance occurs in variation of transfer coefficient. This resonance point is characterized by a parameter SnPrX2/3 which is derived from a similarity relation. In the last part of this paper, the effect of pulsating flow on the time-averaged transfer coefficient is discussed.
