I had in mind that you might have a different view, that's why I show you a drawing

So, maybe I can ask you:
What is the theoretical energy difference required to run the pump in "C" compared to "B"?
Is it E_C = PI / (E_B x 2)

EDIT:
In "A" it should not require energy to run the pump - because there is no pump function, no mass displacement in the tube.
In "B" it obviously require energy to run the pump - because of coriolis effect due to radial mass displacement
In "C" I am not sure - If the radial mass displacement that creates the Coriolis force in the first place, is "gained" back at the bend, it means it will not require energy to displace mass (???)

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