Abstract
The use of surge tanks in hydroelectric projectss is very important to prevent pipes from breaking. Hydroelectric dam construction is very costly, and therefore it is important to protect them against shock waves caused by disconnecting and connecting the flow control valves leading to the turbines. In this study, the rigid column theory and its governing equations are introduced, and then they are solved by the finite difference numerical method. The MS Excel software is used for ease of work, and pressure and velocity fluctuation graphs are provided in the surge tank. Results show that rigid column theory can be implemented easily to find water head and velocity fluctuations in the surge tank. The amplitude of water head fluctuations decreased with the increase in shaft diameter, indicating the positive effect of larger diameter. A 50% increase in the diameter of the vertical shaft does not appreciably change the velocity fluctuations. With increasing friction factor (f), the frequency of the head and velocity decreases. Meanwhile, for increasing f = 0.011 to f = 0.022, the amplitude of the head and velocity is diminished.