Surge tank water level variations following rapid valve opening

An investigation into the movement of the water surface in a surge tank following rapid valve opening is described. At the instant the valve is opened an allowance is made for some flow from the supply pipeline in addition to that from the surge tank and therefore the theory is altered only in the initial conditions. A program was written for a small desk-top calculator linked to a graph plotter to give a visual presentation of the finite difference solutions. Comparison was made with experimental values of the maximum downsurge observed in a model surge tank.