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The news is that someone worked out the maths behind it and wrote it down - then proved they were right.

It's a bit like the fact that everyone knows the shower curtain will billow towards them in the shower but no one has managed to prove why that happens.

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Indeed. There are a few hypotheses about it [1]

[1] https://en.wikipedia.org/wiki/Shower-curtain_effect

I can definitely imagine this being really hard to work out in an equation, but I'm somewhat surprised that this implies that it has been difficult to come up with experiments that would give data that might help figure this out. Surely we have ways of measuring air vortices and pressure that would clarify a lot of what is happening to the air flow?

Funny coincidence! I thought about this when I showered this morning. The water probably sucks air down the drain with it, causing slightly negative pressure causing the curtain to bellow inwards.

Down the drain? I might buy the water sucking down air, but down the drain?

Isn't the point of traps largely to prevent air from traveling either direction through the drain?

I'd love to be on the grants committee when someone requests funding to set up a shower in their lab.

The thing that makes this more interesting is that if you have a large shower (eg a wheelchair wetroom) then the shower curtain behaves differently depending on where you are inside it. Try walking up and down your bathtub next time you have a shower.

The explanation for it might have consequences for a lot of other models though, no?

Great answer, cheers

The shower thing is explained by the coanda (Bernoulli) effect.

"The problem of identifying the cause of this effect has been featured in Scientific American magazine, with several theories given to explain the phenomenon but no definite conclusion."

According to a quick googling, not really.

According to you. Another answer says it's convection. So not so intuitive after all ;)

> the coanda (Bernoulli) effect

Those are two different effects.

Because the hot air inside rises and cooler air pushes inward. It's called convection, and I don't thing anyone needs to run a simulation and publish a paper solving the "shower curtain problem" just because it hasn't been "done" before.

If the water is air-temperature or colder, then curtain does or doesn't blow inward? Care to make make a prediction based on your theory?

Straight from the first paragraph of the Hypotheses section, emphasis mine.

>Also called Chimney effect or Stack effect, observes that warm air (from the hot shower) rises out over the shower curtain as cooler air (near the floor) pushes in under the curtain to replace the rising air. By pushing the curtain in towards the shower, the (short range) vortex and Coandă effects become more significant. However, the shower-curtain effect persists when cold water is used, implying that this cannot be the only mechanism at work.

Scientists investigate and prove things that are "common sense" things all the time because the "common sense" answer turns out to be wrong.

scientists have been arguing about the exact physical forces in this problem for a long time (similarly true for airplane wings). We like to actually confirm our theories with experimental data, and often times, these sorts of papers help the field in unexpected ways in the long term.

It has been done before. See the physics winner for 2001: https://improbable.com/ig/ig-pastwinners.html

I like that it took him two weeks of compute time and it's only a "partial solution"

That's fluid dynamics for you. :-/

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