My last take on this problem only included h as a function of time h(t). I have concluded that this is incorrect in that the height of the water in the tank also effects the flow in the discharge pipe. Thus Q is a nested function of both h and V i.e. Q(h(t),V) , as Werner had pointed out my previous version may not be physically correct because V was not taken into account. Although, the previous version solve blocked worked I have concluded that Werner was correct and that the answer is incorrect due to not taking into account the change in velocity with height. I therefore redone the worksheet to include V in the solve block and change the weir equation with a more physically accurate version. Now unfortunately the solve block is complaining about scalars. I think I have tried every ODE combination of vaiable but all to no avail. Can anyone spot the problem?
Thanking you in advance
Mark