Self-study terms of fluid mechanics explain vacuum degree, head loss, steady flow, nozzle outflow, open channel flow and weir flow. ! !

Vacuum degree: the ratio of vacuum to atmospheric pressure, expressed in percentage;

Head loss: the mechanical energy lost by overcoming the resistance of water flow in the unit weight of water body;

Constant flow rate: the flow rate of the flow elements at any given point that does not change with time;

Nozzle outflow: a short pipe with a diameter of 3-4 times is connected to the orifice of the container wall, and water flows out through the short pipe, and the outlet section is covered with pipes.

Open channel flow: the flow with free water surface in natural rivers, artificial channels or some hydraulic structures;

Weir flow: an open water flow that flows through the top of the water structure and overflows on the upper surface without restriction.