Hydrostatic Pressure - Thermodynamics:
It is also called as Pressure due to Depth of Fluid. It is needed to determine the pressure exerted by static fluid column on surface, which is drowned under it. This type of situations arises in water filled boilers, petrol/diesel filled tank in IC engines, aviation fuel stored in the containers of gas turbines etc.
This pressure is called as 'hydrostatic pressure' as it is caused because of static fluid. The hydrostatic pressure is equal in all the directions on lateral surface of tank. Above formula is applicable for gases also. But because of very small value of p (and w), its effect is hardly felt. Thus, it is usually neglected in thermodynamic calculations. One such tank is shown in the figure given below. It contains homogeneous liquid of weight density w. The pressure p exerted by it at depth h can be given by