Numerical investigation of the stabilization of the no-motion state of a fluid layer heated from below and cooled from above

The feasibility of controlling flow patterns of Rayleigh-Benard convection in a fluid layer confined in a circular cylinder heated from below and cooled from above (the Rayleigh-Benard problem) is investigated numerically. It is demonstrated that, through the use of feedback control, it is possible to stabilize the no-motion (conductive) state, thereby postponing the transition from a no-motion state to cellular convection. The control system utilizes multiple sensors and actuators. The actuators consist of individually controlled heaters positioned on the bottom surface of the cylinder. The sensors are installed at the fluid's midheight. The sensors monitor the deviation of the fluid's temperatures from preset desired values and direct the actuators to act in such a way so as to eliminate these deviations. The numerical predictions are critically compared with experimental observations. (C) 1998 American Institute of Physics.