What is a hole and describe the flow of water in a hole?

Question

rapids on a river

Answer 1

In engineering class the main discussion of a hole was a area in the surface of a resevoir that ws significantly smalller than the surface. most of the study was focused on the rate of flow in the vicinity of the hole. the flow just outside the resevoir closely matches a pipe of the same cross section. the flow rate drops of quickly as you measure away from the hole. the details require calculus. is that the kind of answer you need?