Convective Instability of Rotating Radiating Fluids

1980 ◽  
Vol 102 (2) ◽  
pp. 268-272 ◽  
Author(s):  
S. O. Onyegegbu

The Benard problem of a rotating radiating nongray fluid is examined analytically for both stationary and oscillatory convection. Radiation is modeled by the Milne-Eddington approximation. The time derivatives are retained in the disturbance equations and both types of instability were studied using the same approximating functions. Results presented show that, in the presence of rotation, radiation increases the zone in which overstability is the preferred mode of instability.

1975 ◽  
Vol 80 (1) ◽  
pp. 76-88 ◽  
Author(s):  
J.C. Legros ◽  
D. Longree ◽  
G. Chavepeyer ◽  
J.K. Platten

Using linear stability theory and numerical simulations, we demonstrate that the critical Rayleigh number for bifurcation from the no-motion (conduction) state to the motion state in the Rayleigh–Bénard problem of an infinite fluid layer heated from below and cooled from above can be significantly increased 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 or velocity are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behaviour at relatively low Rayleigh numbers.


Nonlinearity ◽  
2020 ◽  
Vol 33 (11) ◽  
pp. 5686-5732
Author(s):  
Piotr Kalita ◽  
Grzegorz Łukaszewicz

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