Origin of the pressure differences around a sail. Full details in paper linked in description.
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Published 2023-04-29
This video captures results from experimental work undertaken during the development of a paper explaining the source of the pressure differences around a sail. Links to the paper above.
The paper explains how the source of the pressure difference is inadequately explained in the literature and presents a thought experiment and a physical experiment examining how air moves around a foil using a single layer of soap bubbles.
All Comments (4)
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Nice visualization. I've been doing this with pepper on water for years, super helpful in the classroom but I never video taped it.
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You should have dropped food coloring on ONE bubble that went over and one under. They distort a lot ,stick together and to the sail simulating high viscosity. I believe that also masks the speed changes, however, there is clearly acceleration because the bubbles start motionless, then move. Lego CFD. . .
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Another issue I realize is that you have nothing simulating atmospheric pressure. The bubbles simply float on the water under the glass and nothing is pushing to compress them together as atmospheric pressure does. If you put two squeegees together, then separate them to simulate a vacuum, the bubbles will stay there they as they are being held to the glass by their surface tension as bubbles do. Motions here are controlled by the bubble stickiness, not an ambient pressure and changes therein.
