Search results
Results from the WOW.Com Content Network
In engineering, the Moody chart or Moody diagram (also Stanton diagram) is a graph in non-dimensional form that relates the Darcy–Weisbach friction factor f D, Reynolds number Re, and surface roughness for fully developed flow in a circular pipe. It can be used to predict pressure drop or flow rate down such a pipe.
In fluid dynamics, the entrance length is the distance a flow travels after entering a pipe before the flow becomes fully developed. [1] Entrance length refers to the length of the entry region, the area following the pipe entrance where effects originating from the interior wall of the pipe propagate into the flow as an expanding boundary layer.
Not all flow within a closed conduit is considered pipe flow. Storm sewers are closed conduits but usually maintain a free surface and therefore are considered open-channel flow. The exception to this is when a storm sewer operates at full capacity, and then can become pipe flow. Energy in pipe flow is expressed as head and is defined by the ...
For flow in a pipe of diameter D, experimental observations show that for "fully developed" flow, [n 2] laminar flow occurs when Re D < 2300 and turbulent flow occurs when Re D > 2900. [13] [14] At the lower end of this range, a continuous turbulent-flow will form, but only at a very long distance from the inlet of the pipe. The flow in between ...
A flow that is not a function of time is called steady flow. Steady-state flow refers to the condition where the fluid properties at a point in the system do not change over time. Time dependent flow is known as unsteady (also called transient [8]). Whether a particular flow is steady or unsteady, can depend on the chosen frame of reference.
Couette flow – Model of viscous fluid flow between two surfaces moving relative to each other; Effusive limit; Free molecular flow – Gas flow with a relatively large mean free molecular path; Incompressible flow – Fluid flow in which density remains constant; Inviscid flow – Flow of fluids with zero viscosity (superfluids)
A good estimate of a fully developed velocity profile can be used for those without adequate equipment to actually measure the flow velocities within the pipe. The following straight pipe equivalent length in eq.(3) was utilized to ensure a fully developed flow profile exists. [6]
A Graetz number of approximately 1000 or less is the point at which flow would be considered thermally fully developed. [ 2 ] When used in connection with mass transfer the Prandtl number is replaced by the Schmidt number , Sc, which expresses the ratio of the momentum diffusivity to the mass diffusivity.