We have studied the characteristics of heat-transfer in strongly time-dependent thermal convection for base-heated, infinite Prandtl number fluids within the Boussinesq approximation. The range of the Rayleigh number studied lies between 5 × 105 and 108. Typically, flows at Rayleigh number around 106 consist of large-scale cells with intermittent boundary-layer instabilities. For Ra greater than 107 the heat-transfer mechanism changes from one, characterized by mushroom-like plumes, to one consisting of disconnected upward rising instabilities. The Nusselt numbers of the time-dependent flows are smaller than the steady-state values. This discrepancy between the steady-state and time-dependent Nusselt numbers increases with Ra and reaches around 30% for Ra = 108.
|Original language||English (US)|
|Number of pages||4|
|Journal||American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD|
|State||Published - Dec 1 1990|
|Event||Winter Annual Meeting of the American Society of Mechanical Engineers - Dallas, TX, USA|
Duration: Nov 25 1990 → Nov 30 1990