- Volumetric flow rate
The volumetric flow rate in
fluid dynamics andhydrometry , (also known as volume flow rate or rate of fluid flow) is the volume of fluid which passes through a given surface per unit time (for examplecubic meters per second [m3 s-1] inSI units, or cubic feet per second [cu ft/s] ). It is usually represented by the symbol "Q".Volumetric flow rate should not be confused with volumetric
flux , represented by the symbol "q", with units of m3/(m2 s), that is, m s-1. The integration of a flux over an area gives the volumetric flow rate. Volumetric flow rate is also linked toviscosity .Given an
area "A", and a fluid flowing through it with uniformvelocity "v" with an angle θ away from theperpendicular to "A", the flow rate is::Q = A cdot v cdot cos heta.In the special case where the flow is perpendicular to the area A, that is, θ = 0, the volumetric flow rate is: :Q = A cdot v.
If the velocity of the fluid through the area is non-uniform (or if the area is non-planar) then the rate of fluid flow can be calculated by means of a
surface integral ::Q = iint_{S} mathbf{v} cdot d mathbf{S}
where "d"S is a differential surface described by::dmathbf{S} = mathbf{n} , dA with n the unit
surface normal and "dA" the differential magnitude of the area.If a surface "S" encloses a volume "V", the
divergence theorem states that the rate of fluid flow through the surface is the integral of thedivergence of the velocityvector field v on that volume::iint_Smathbf{v}cdot dmathbf{S}=iiint_Vleft( ablacdotmathbf{v} ight)dV.
ee also
*
Air to cloth ratio
*Darcy's law
*Discharge (hydrology)
*Flowmeter
*Flux (transport definition)
*Mass flow rate
*Orifice plate
*Poiseuille's law
*
Wikimedia Foundation. 2010.