The "Chimney Effect" theory makes a lot of sense, as everyone knows that hot air rises. However, inward movement continues even when only cold water is used. Therefore, other forces must be involved. The Bernoulli Effect refers to the flow of water downward causing an increase in velocity, which decreases air pressure within the shower. This decrease in air pressure results in an "air pressure differential".
One can only assume these "effects" work together, causing lightly weighted curtains to be sucked inward.
You probably need a heavier curtain
The best way of putting an end to shower curtain cling is to buy a heavy weight curtain that is made to stand up to the effects shown in the picture above. These are quite cheap and highly rated.
>Click here to read my blog post on heavy weight curtains<
If you like the curtain you have, and would rather not replace it, there are several ways of adding extra weight or using devices specifically designed to hold the curtain out while you're showering. I've tracked down all of the most commonly used products and popular methods people use to solve this problem.
Check out my blog post 5 Ways To Stop Your Shower Curtain Blowing In
Another simple idea I should mention is that the air pressure and hot air rising problems can be minimized to a certain extent by raising the curtain upward a little to allow for some air movement underneath. I haven't tried this approach myself but have read that it can help to minimize the problem.
If you're looking for a quick fix, the image below shows a commonly used technique, but it can be a bit of a pain having to do this every morning.
It's not really a "solution" as wrestling the curtain into position every morning and making the little puddle can be a pain.
Check out the other posts in this blog for a wide range of ideas and solutions. The tips and tricks presented here will give you several different options for eliminating this infuriating problem.