Active control of convection

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:175482

Bau, H H ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)

Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

• Research Organization: Argonne National Lab., IL (United States)
• OSTI ID: 175482
• Report Number(s): CONF-9505200--; ON: DE96000983
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
66 PHYSICS
BIFURCATION
CONTROL
CONVECTION
FLUID FLOW
INSTABILITY