The Influence of the Magnitude of Gravitational Acceleration on Marangoni Convection About an Isolated Bubble under a Heated Wall

O’Shaughnessy, S.M.; Robinson, A.J.

doi:10.1080/01457630902922251

Cited by 10 publications

(16 citation statements)

References 26 publications

(46 reference statements)

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“…The opposing influences provoke a counter-rotating sheardriven secondary vortex as depicted in Figure 8. This behaviour has been observed in [20,22,32]. From the figure it is evident that with increasing gravitational acceleration, and therefore increasing buoyancy effect, the thermocapillary effect becomes progressively more confined to a region close to the bubble.…”

Section: Influence Of Ramentioning

confidence: 48%

“…In [22], O'Shaughnessy and Robinson investigated the influence of the Rayleigh number for a fixed Marangoni number and found that the gravity level affected the velocity profile by modifying the interfacial temperature gradient, but that the location of maximum velocity was almost independent of gravity level. It was also shown that increased gravity levels cause a reduction in the effective radius and area of enhancement around the gas bubble.…”

Section: Bhunia and Kamotani [Ref] Numerically Investigated 2dmentioning

confidence: 99%

“…O'Shaughnessy and Robinson [13,21,22] were the first to numerically simulate thermal Marangoni convection with the expressed goal of quantifying the local wall heat transfer distribution around the bubbles. In [13] they investigated the influence of increasing the Marangoni number in 0-g and determined that thermocapillary convection enhanced the local heat flux to over 65% when compared with pure conduction.…”

Section: Bhunia and Kamotani [Ref] Numerically Investigated 2dmentioning

confidence: 99%

“…The influence of the magnitude of gravitational acceleration on Marangoni convection about an isolated bubble on a heated wall has been numerically investigated in [22]. To study the response to changing gravitational field strength, simulations were initially performed for a range of gravity levels at a fixed Marangoni of Ma =363, which corresponded to the largest temperature gradient imposed on the channel experimentally (~50°C).…”

Section: Influence Of Ramentioning

confidence: 99%

“…In [13,22], simulations were performed using a Pr = 83 fluid and Marangoni numbers in the range 183≤Ma≤915. Using the same computational grid, the simulations performed in this study concern a Pr = 220 fluid in the range 145≤Ma≤363.…”

Section: Combined Influence Of Pr Ra and Mamentioning

confidence: 99%

See 4 more Smart Citations

Heat transfer near an isolated hemispherical gas bubble: The combined influence of thermocapillarity and buoyancy

O’Shaughnessy

Robinson

2013

International Journal of Heat and Mass Transfer

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Thermal Marangoni convection about a 1 mm radius hemispherical air bubble attached to a heated wall immersed in a silicone oil layer of constant depth of 5 mm was numerically investigated. Tests were performed for a range of Marangoni numbers (145≤Ma≤915) with varying levels of gravitational acceleration between zero gravity and earth gravity in order to quantify the rates of heat transfer. For the zero gravity condition, a thermocapillary-driven vortex develops around the bubble extending the entire height of the channel. This flow structure causes a jet-like flow of heated liquid to emanate from the bubble tip which impinged on the cold wall. With the addition of gravity, a counter rotating secondary buoyancydriven vortex forms which reduces the size of the thermocapillary vortex and disrupts the jet flow from the bubble tip. The wall heat flux profiles indicate that under zero gravity, the peak heat fluxes increase monotonically with Ma with an area of influence that increases asymptotically with Ma. Likewise, under gravity conditions the peak heat flux also increases with Ma and for low Ma is higher than that of 0-g. However, the area of influence is considerably smaller and not sensitive to Ma or the level of gravity. Experimental validation of selected terrestrial gravity numerical results was obtained using particle image velocimetry (PIV) for low to moderate Marangoni numbers. For all experiments, steadystate Marangoni convection was observed. The experimental flow patterns showed good agreement with the numerical solutions.

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Section: Influence Of Ramentioning

confidence: 48%

Section: Bhunia and Kamotani [Ref] Numerically Investigated 2dmentioning

confidence: 99%