TRANSIENT OSCILLATORY CONJUGATE NATURAL-CONVECTION IN A TALL WATER CAVITY

Abstract

A two-dimensional numerical simulation was conducted to investigate the effects of the heat capacity of the heated wall on the transient oscillatory convection in a tall cavity. Results were particularly obtained for water (Pr = 6) in a tall cavity (A = 6) with constant-heat-flux heating on one side and isothermal cooling on the opposing side. Significant wall heat capacity effects were found. Specifically, a heated wall of finite heat capacity can slow down the flow evolution process to steady state at low Rayleigh number and damp the flow oscillation during the initial developing period at high Rayleigh number. In periodic flow at Ra(H)* = 4.4 x 10(10) the wall heat capacity significantly reduces the amplitude of the temperature oscillation. A quasi-periodic flow at Ra(H)* = 4.8 x 10(10) was found to become periodic when the wall heat capacity was included. The wall heat capacity does not shown noticeable effect when the flow is chaotic for Ra(H)* = 6.0 x 10(10).