Waterkolom

Waterkolom, or water column, is a term used in fluid mechanics to describe a vertical column of water whose height represents the pressure head in a fluid system. It is a simple way to illustrate how pressure varies with depth in a static fluid; the pressure at a point at depth h below the top of the column equals P = rho g h, where rho is the water density and g is gravitational acceleration.

Under standard conditions, freshwater density is about 1000 kg/m3 and g is approximately 9.81 m/s2, so a water column of about 10.3 meters balances atmospheric pressure, roughly 1 atmosphere. This relation underpins devices such as water barometers and simple manometers, where differences in water level correspond to pressure differences.

Water columns are used in hydraulic and civil engineering to estimate pressure in pipes and tanks, in hydrology to represent groundwater or well head, and in the design of pumps and regulators where pressure heads are expressed in meters of water. In open-topped systems, the height of the water column determines the available energy to push water through a system.

Limitations include the influence of temperature on density and the presence of salinity; in dynamic systems, acceleration, viscosity, and flow disturbances mean the simple hydrostatic relation P = rho g h applies only locally.