Flow rate Q is defined as the volume V flowing past a point in time t. The SI unit of flow rate is (m^3)/s, but other rates can be used, such as L/min. Flow rate and velocity are related by the produc...Flow rate Q is defined as the volume V flowing past a point in time t. The SI unit of flow rate is (m^3)/s, but other rates can be used, such as L/min. Flow rate and velocity are related by the product of the cross-sectional area of the flow by its average velocity. The equation of continuity states that for an incompressible fluid, the mass flowing into a pipe must equal the mass flowing out of the pipe.
