My first post, so hope it's in the right place! If water flowing at 2 m/s in an open channel (say 2m deep by 3m wide) flows into a circle (call the entry angle 30degrees), what happens to the speed of the water? The dimensions are just examples, it's the theory I'm interested in. I know the velocity changes (as it's a vector, and the direction in the circle is always changing), but what happens to the water speed? Put it another way - if you put your hand in the water in the open channel, and then you put your hand in the water swirling around the circle, would it be obviously a stronger (ie faster) current? I'm not too worried about the effect of friction, and we can also ignore the fact that the water has to go somewhere once it gets all the way around the circle to the start (ie where the straight channel joins the circle). Unless you think either of those scenarios are either relevant or interesting to consider! I guess I'd also be interested to know how long the water takes to go around the circle. Please include any forces (centripetal, centrifugal, AV, gravitational, upthrust) that are relevant to furthering my understanding. I've looked some of these up, but they have yet to make sufficient sense for my basic question to be answered by them! I know it's a complicated question, but if you could please answer it in as simple a manner as possible that would be great. Please include your formulas so I can see how you derive things, and where you have inserted values. Thanks for any answers and / or links you can give.