Flow through a hole at the bottom of a tank
 

Hello all,
I'm trying to simulate (transient) flow through a hole at the bottom of a tank. It can be solved by a simple Bernoulli's equation but I want to perform CFD for this case. It doesn't have an inlet, but should already have water inside which flows through the holes or exit at the bottom of the tank. I want to know how long it takes to completely empty the tank. Fig attached.
Is it even possible to perform CFD for such a case?