Flow/Pressure Relationship

Flow increases with pressure. They have a direct relationship. In plumbing a pressure tanks is used to induce flow through pipes. Flow decreases as pressure subsides until the water pump turns on increasing the pressure in the holding tank. Contract plumbers size the water tank and hysteresis in pressure setting so that flow can be regulated by throttle vavles rather than indictive of fluctuating pressure in the system while water is being drained.

The question is far too vague. What sort of system? Do you mean actual pressure or differential pressure? Both could be relevant, specially for compressible fluids. In most situations flow is turbulent and differential pressure varies as flow². For laminar flow, differential pressure varies as flow_^.

Cheers.........Codey

Compressible flow, (eg compressed air) is normally limited to the speed of sound, approximately 1120 fps. At higher pressure the air (gas) is more dense. Two pounds of air at 1120 fps is greater than one pound at 1120 fps. Below the critical ratio, P2/P1 = 53%, compressed air will accelerate and be denser at higher pressure therefore an increase in pressure increases flow by both density and velocity.

Liquid is basically non-compressible and the velocity caused by higher pressure increases the mass of flow. (Pressure F = ma). There has got to be a top limit on velocity but when you see a water jet cutting steel or cement it seems that may be enough.