Buoyancy effects in plane Couette flow heated uniformly from below with constant heat flux

Choi, Chi Kyu; Chung, T. J.; Kim, Min Chan

doi:10.1016/j.ijheatmasstransfer.2003.12.010

Cited by 14 publications

(7 citation statements)

References 26 publications

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“…A different path for the definition of a value of n would be to adjust it to make the growth rate of the base state and that of the first order disturbances equal. In the case of an imposed step heat flux, this leads to n = 1/2 [23,24]. Anyhow, results are weakly dependent on such choice.…”

Section: Solution Methodsmentioning

confidence: 99%

The onset of natural convection in lakes and reservoirs due to night time cooling

Ihle

Niño

2011

Environ Fluid Mech

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A theoretical model, based on linear stability analysis, is proposed to predict the onset of natural convection in lakes and reservoirs due to night time cooling. To such purpose, the system was modelled as a initially quiescent deep Boussinesq fluid reservoir, whose upper boundary temperature changes sinusoidally. From scaling analysis, it is found that critical onset times for convection are proportional to R −2/7 , where R is a Rayleigh number including fluid properties and forcing frequency. The proportionality constant was found, from the solution of an eigenvalue problem, as a function of the Prandtl number. The onset time for convection was easily observed from experiments and quantitatively detected as a rapid increase of the RMS of the computed velocity field obtained using PIV. In this controlled conditions, differences close to 10% between predicted and observed times for the start of the convective flow was found. It is apparent from the present set of results that predictions are reasonable.

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Section: Solution Methodsmentioning

confidence: 99%

The onset of natural convection in lakes and reservoirs due to night time cooling

Ihle

Niño

2011

Environ Fluid Mech

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“…For the traveling transverse rolls Eq. (5) can be changed to the following periodic disturbances at R=R c, 0 : (8) where 'c.c.' denotes the corresponding complex conjugates and ω c is the imaginary part of σ(=σ i ).…”

Section: Linear Stability Analysismentioning

confidence: 99%

“…In a horizontal porous layer with through flow Hsu and Cheng [5] analyzed the critical position marking the onset of vortex instability. Choi and his colleague studied stationary vortex instability in a fluid and fluid-saturated porous layer with propagation theory and experiment [6][7][8]. Lee et al [9] expected the onset of mixed convection in an inclined surface embedded porous media heated from below with propagation theory.…”

Section: Introductionmentioning

confidence: 99%

The spatiotemporal instability on mixed convection in porous media

Chung

Kim

Choi

2009

Korean J. Chem. Eng.

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The absolute and convective instability on mixed convection in porous media is examined, and the phase transition from the oscillatory wave motion to the stationary vortex one is observed. Based on linear and weakly nonlinear analyses, the critical conditions to mark the onset of traveling transverse rolls are analytically obtained for small Péclet numbers. The flow change from transverse wave to longitudinal vortex is reproduced by numerical simulation. These criteria made good agreement with the available experiment data.

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“…Nicolas et al [9] placed a sinusoidal mechanical excitation in the channel inlet to trigger the steady longitudinal rolls to become wavy, unsteady and periodic, 5 which in turn provided a more uniform time-averaged deposition in the channel. Choi et al [10] employed a linear theory to solve the problem of the thermal stability of a fluid above a heated bottom plate with a constant heat flux. Their results showed that the critical Rayleigh number of the longitudinal rolls increased with decreasing Prandtl number.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Three-Dimensional Mixed Convection in a Horizontal Channel Using a Baffle

Chang

2015

Heat Transfer Engineering

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Three-dimensional mixed convection inside a horizontal rectangular channel with a square heated surface on one of the vertical sidewalls and an infinitely thin baffle installed on the opposite insulated sidewall is numerically investigated. Attention is focused on the influence of the baffle position (−2 to 2), the inclination angle between the baffle and the horizontal (15° to 90°), and the baffle height (0.2 to 0.9) on the flow and thermal characteristics. The other parameters remain unchanged: the Reynolds number (100), Grashof number (50 000) and Prandtl number (0.71). The results show recirculation around the top portion of the heated surface due to strong buoyancy. The heat transfer depends strongly on the relative positions of the baffle and the recirculation. Heat transfer enhancement is obtained with a higher baffle and a Downloaded by [North Dakota State University] at 12:06 18 February 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2 larger inclination angle if the baffle is close to the cold main stream. In contrast, the average Nusselt number is slightly smaller if the baffle is surrounded by the recirculation than it is without the baffle. An accurate correlation is proposed for calculating the average Nusselt number over the investigated range of the baffle position and the inclination angle for a fixed baffle height (0.75).

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Buoyancy effects in plane Couette flow heated uniformly from below with constant heat flux

Cited by 14 publications

References 26 publications

The onset of natural convection in lakes and reservoirs due to night time cooling

The onset of natural convection in lakes and reservoirs due to night time cooling

The spatiotemporal instability on mixed convection in porous media

Enhanced Three-Dimensional Mixed Convection in a Horizontal Channel Using a Baffle

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