Numerical investigation on transient incompressible fluid flow

In a hydroelectric power plant or in a pumping station in order to avoid sudden large increase of pressure due to instantaneous valve closure sometimes a surge tank can be installed. The height of surge tank is designed by the highest possible water level during the operation. The theoretical treatment of oscillation in a surge tank is difficult because of the non-linearity of friction term in the governing differential equation of the system. The present study attempts to find a general solution for the surge oscillation in a simple surge tank in terms of non-dimensional parameters. Equations for the highest and the lowest water level in the tank, i.e. very important in the design of a surge tank have been found. A special laboratory apparatus was devised to verify the obtained results. A very good agreement between the obtained equations and the experimental results was found. An adequate selection of involved parameters in the design can lead to very unsatisfactory design. Based on the Reliability theory the range within which the coefficient can be chosen also developed.