Given a tank with a certain height of water above the discharge pipe of know length, open to the atmosphere at the other end. I know the flow rate can be calculated if the pipe was horizontal by using Poiseuille's equation (No entry losses, no turbine or pump work, pipe cross-section is constant) by considering the pressure loss to be equal to the difference between the hydrostatic pressure at the inlet of the pipe and the atmospheric pressure.
If the pipe was not horizontal.. ie the pipe outlet is at a certain distance below the inlet to the pipe, by knowing the length of the pipe and not considering any pipe bend losses can we calculate the flow rate?....I considered using Bernoulli's equation by considering the pressure drop to be equal to the difference between the hydrostatic pressure at the inlet of the pipe and the atmospheric pressure and as the height difference between the inlet and outlet is know. I couldn't figure out how to calculate the pressure loss term in the equation. Is this data sufficient to calculate the flow rate...if not what other data would be required?