Does the volume of water in a tank have any effect on the rate at which the water leaves through a pipe at the bottom of the tank. The diameter of the pipe is fixed

You asked a similar question yesterday in the math forum:

https://www.askmehelpdesk.com/mathematics/flow-rate-tank-377712.html

The answer is NO. The velocity of water flow out of a tank is dependent on (a) the height of water above the exit pipe, and (b) the physical characteristics of the pipe - its diameter, internal roughness, length ,and shape (bent versus straight). It can be very difficult to model how these characteristics effect water flow, so as a first order approximation you simply use the height of the water head, as I described in my answer to your prevoius question.

Note that the width of the water tank (and hence its volume) has no bearing on this. Some people find it had to believe that the size of the tank doesn't matter - but the reality is that a dam that holds back, say, 6 feet of water has a set amount of water pressure on it regardless of whether the lake it contains is 100 feet across or 100 miles. All that matters is how tall the dam is.