Difference between revisions of "Marangoni Effect"
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[http://www.doflick.com/ViewVideo.aspx?t=0&vId=192 Marangoni Effect Example 1] | [http://www.doflick.com/ViewVideo.aspx?t=0&vId=192 Marangoni Effect Example 1] | ||
| − | The tears of wine | + | The tears of wine phenomenon seen in the photo to the right is explained by the Marangoni effect. As alcohol evaporates from a thin layer of wine coating the glass, the surface tension increases. Wine is driven from the bulk up the sides of the glass towards the area of low surface tension until a drop forms, and gravity pulls it back down [2]. |
| − | + | A gradient in chemical concentration causes the surface tension gradient leading to wine tears. [[Influence of Substrate Conductivity on Circulation Reversal in Evaporating Drops|Ristenpart et. al.]] explore a surface tension gradient caused by a thermal gradient across the surface of an evaporating drop. | |
== References == | == References == | ||
Revision as of 22:46, 14 November 2009
Definition
The Marangoni effect is the flow of fluid caused by a gradient in surface tension [1,2]. The gradient in surface tension can be caused by a gradient in temperature or chemical concentration [2]. Fluid flows from a region with low surface tension to a region with high surface tension as seen clearly in the following video: Marangoni Effect Example 1
The tears of wine phenomenon seen in the photo to the right is explained by the Marangoni effect. As alcohol evaporates from a thin layer of wine coating the glass, the surface tension increases. Wine is driven from the bulk up the sides of the glass towards the area of low surface tension until a drop forms, and gravity pulls it back down [2].
A gradient in chemical concentration causes the surface tension gradient leading to wine tears. Ristenpart et. al. explore a surface tension gradient caused by a thermal gradient across the surface of an evaporating drop.
References
[1] Velarde, Manuel, "Drops, Liquid Layers and the Marangoni Effect," Philosophical Transactions: Mathematical, Physical and Engineering Sciences 356 829-844 (1998).
[2] Mei, C., "Lecture 4: Marangoni flows," Fluid Dynamics Lecture Notes (May 5, 2004).
