OPEN-CHANNEL FLOW

OPEN-CHANNEL FLOW OPEN-CHANNEL flow is a flow of liquid (basically water) in a conduit with a free surface. That is a surface on which pressure is equal to local atmospheric surfacePatmPatmClassification of OPEN-CHANNEL FlowsOpen- channel flows are characterized by the presence of a liquid-gas interface called the free Natural flows: rivers, creeks, floods, etc. Human-made systems: fresh-water aquaducts, irrigation, sewers, drainage ditches, channelsNatural channelsArtificial channelsOpen cross sectionCovered cross sectionTotal Head at A Cross Section: The total head at a cross section is: where H=total headZ=elevation of the channel bottomP/g = y = the vertical depth of flow (provided that pressure distribution is hydrostatic)V2/2g= velocity headg2V + P+z=H2avEGLD atumxzy V2/2gQSf :the slope of energy grade lineSw :the slope of the water surfaceEnergy Grade Line & Hydraulic Grade Line in open channel FlowSf:the slope of energy grade lineSw:the slope of the water surfaceSo:the slope of the bottomz1z2 Datum lineChannel bottomEGLy1y2V12/2gV22/2ghf12 open -Cha

Comparison of Open Channel Flow & Pipe Flow 1) OCF must have a free surface 2) A free surface is subject to atmospheric pressure 3) The driving force is mainly the component of gravity along the flow direction. 4) HGL is coincident with the free surface. 5) Flow area is determined by the geometry of the channel …

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  Open, Channel, Open channel

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