Temperature stresses in a semiinfinite plate heated by a moving point source of heat

1979 ◽  
Vol 15 (6) ◽  
pp. 505-509 ◽  
Author(s):  
A. N. Kulik
Keyword(s):  
Point Source ◽  
Temperature Stresses ◽  
Semiinfinite Plate ◽  
Point Source Of Heat

Control problem with a point source of heat used as a controller

2010 ◽  
Vol 82 (3) ◽  
pp. 971-973 ◽  
Author(s):  
M. Otelbaev ◽  
A. Hasanov ◽  
B. Akpayev
Keyword(s):  
Point Source ◽  
Control Problem ◽  
Point Source Of Heat

Free convection above a point source of heat in a stratified fluid

1981 ◽  
Vol 16 (2) ◽  
pp. 180-188 ◽  
Author(s):  
V. S. Tupitsyn ◽  
Yu. D. Chashechkin
Keyword(s):  
Free Convection ◽  
Point Source ◽  
Stratified Fluid ◽  
Point Source Of Heat

Doubly Diffusive Convection Due to a Point Source at Various Depths in a Stratified Fluid

1999 ◽  
Vol 15 (1) ◽  
pp. 27-33
Author(s):  
Chin-Hwa Kong ◽  
Chi-Min Liu ◽  
Ray-Yeng Yang
Keyword(s):  
Point Source ◽  
Differential System ◽  
Stratified Fluid ◽  
Linear Differential System ◽  
Similar Form ◽  
Diffusive Instability ◽  
Quantitative Estimates ◽  
Diffusive Convection ◽  
Linear Differential ◽  
Point Source Of Heat

ABSTRACTThe problem of a stable stratified fluid heated by a point source of heat at various depths is treated in this paper. A hot plume is formed with a series of layer around and above it. Quantitative estimates for the criterion of onset of doubly diffusive instability are obtained in this work. The linear differential system governing stability is then solved. The results show that the stationary onset of this doubly diffusive problem caused by a point source may be led to a similar form of small-gap Taylor- Couette problem.

Generation of collimated jets by a point source of heat and gravity

2001 ◽  
Vol 449 ◽  
pp. 39-59 ◽  
Author(s):  
VLADIMIR SHTERN ◽  
FAZLE HUSSAIN
Keyword(s):  
Point Source ◽  
High Speed ◽  
Boussinesq Equations ◽  
Threshold Value ◽  
Onset Of Convection ◽  
Rest State ◽  
Electrically Conducting ◽  
Point Source Of Heat ◽  
The Stability ◽  
Astrophysical Flows

New solutions of the Boussinesq equations describe the onset of convection as well as the development of collimated bipolar jets near a point source of both heat and gravity. Stability, bifurcation, and asymptotic analyses of these solutions reveal details of jet formation. Convection (with l cells) evolves from the rest state at the Rayleigh number Ra = Racr = (l − 1)l(l + 1)(l + 2). Bipolar (l = 2) flow emerges at Ra = 24 via a transcritical bifurcation: Re = 7(24 − Ra)/(6 + 4Pr), where Re is a convection amplitude (dimensionless velocity on the symmetry axis) and Pr is the Prandtl number. This flow is unstable for small positive values of Re but becomes stable as Re exceeds some threshold value. The high-Re stable flow emerges from the rest state and returns to the rest state via hysteretic transitions with changing Ra. Stable convection attains high speeds for small Pr (typical of electrically conducting media, e.g. in cosmic jets). Convection saturates due to negative ‘feedback’: the flow mixes hot and cold fluids thus decreasing the buoyancy force that drives the flow. This ‘feedback’ weakens with decreasing Pr, resulting in the development of high-speed convection with a collimated jet on the axis. If swirl is imposed on the equatorial plane, the jet velocity decreases. With increasing swirl, the jet becomes annular and then develops flow reversal on the axis. Transforming the stability problem of this strongly non-parallel flow to ordinary differential equations, we find that the jet is stable and derive an amplitude equation governing the hysteretic transitions between steady states. The results obtained are discussed in the context of geophysical and astrophysical flows.

Melting of a semiinfinitely large body by an internal point source of heat

1973 ◽  
Vol 24 (3) ◽  
pp. 378-383 ◽  
Author(s):  
G. E. Gorelik ◽  
N. V. Pavlyukevich ◽  
T. L. Perel'man ◽  
G. I. Rudin
Keyword(s):  
Point Source ◽  
Large Body ◽  
Internal Point ◽  
Point Source Of Heat

scholarly journals Transient ventilation dynamics following a change in strength of a point source of heat

2008 ◽  
Vol 614 ◽  
pp. 15-37 ◽  
Author(s):  
D. J. BOWER ◽  
C. P. CAULFIELD ◽  
S. D. FITZGERALD ◽  
A. W. WOODS
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Point Source ◽  
Intermediate Layer ◽  
Laboratory Experiments ◽  
Lower Layer ◽  
Low Level ◽  
Good Accord ◽  
Point Source Of Heat ◽  
Intermediate Density

We investigate the transient ventilation flow within a confined ventilated space, with high- and low-level openings, when the strength of a low-level point source of heat is changed instantaneously. The steady-flow regime in the space involves a turbulent buoyant plume, which rises from the point source to a well-mixed warm upper layer. The steady-state height of the interface between this layer and the lower layer of exterior fluid is independent of the heat flux, but the upper layer becomes progressively warmer with heat flux. New analogue laboratory experiments of the transient adjustment between steady states identify that if the heat flux is increased, the continuing plume propagates to the top of the room forming a new, warmer layer. This layer gradually deepens, and as the turbulent plume entrains fluid from the original warm layer, the original layer is gradually depleted and disappears, and a new steady state is established. In contrast, if the source buoyancy flux is decreased, the continuing plume is cooler than the original plume, so that on reaching the interface it is of intermediate density between the original warm layer and the external fluid. The plume supplies a new intermediate layer, which gradually deepens with the continuing flow. In turn, the original upper layer becomes depleted, both as a result of being vented through the upper opening of the space, but also due to some penetrative entrainment of this layer by the plume, as the plume overshoots the interface before falling back to supply the new intermediate layer. We develop quantitative models which are in good accord with our experimental data, by combining classical plume theory with models of the penetrative entrainment for the case of a decrease in heating. Typically, we find that the effect of penetrative entrainment on the density of the intruding layer is relatively weak, provided the change in source strength is sufficiently large. However, penetrative entrainment measurably increases the rate at which the depth of the draining layer decreases. We conclude with a discussion of the importance of these results for the control of naturally ventilated spaces.

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