TRANSIENT OSCILLATORY CONJUGATE NATURAL-CONVECTION IN A TALL WATER CAVITY

A two-dimensional numerical simulation was conducted to investigate th e effects of the heat capacity of the heated wall on the transient osc illatory convection in a tall cavity. Results were particularly obtain ed 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. Sign ificant 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 d uring the initial developing period at high Rayleigh number. In period ic 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 w all 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).