Hi

I have a tank being filled via a pipe at the bottom from the sea through a know diametre.

All units in metres and seconds.

I can plot the decrease in flow rate on a graph from where the tank is empty ( flow rate is high ) untill the tank is full and flow rate slows untill equalizing. I use the eqation for velocity v = sqrt 2*g*h to plot on the vertical and the formula q=d^2*v*pi/4 (flow rate) along the horizontal axis.And get a nice neat curve,

But what does the area under the curve represent and how can i use it.

I would like to be able to find what the volume of water is at each change in the velocity .

Thanks

Rob