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Gondia Education Society's C.J. Patel College, Tirora , Dist.- Gondia 441911. Subject : FLUVIAL GEOMORPHOLOGY Topic 1 ) LAMINAR & TURBULENT 2) UNIFORM & NON UNIFORM Is presented by Dr. Nanabhau S. Kudnar M.A., B.Ed., SET, NET, Ph.D., M.B.A . Head, Department of Geography C.J . Patel College Tirora .


LAMINAR FLOW DEFINATION : Fluid with a high viscosity will flow more slowly & will generally not support eddy currents & therefore the internal roughness of the pipe will have no effect on the frictional resistance. The condition is known as LAMINAR FLOW. Some time this flow also known as streamline flow . Flow occurs when a fluid flows in parallel layers , with no distruption between the layers.


In laminar flow the motion of the particles of fluid is very orderly with all particles moving in straight lines parallel to the pipe wall. Influid dynamic, laminar flow is a flow regime characterized by high momentum diffusion & low momentum convection. In nonscientific terms laminar flow is SMOOTH. The dimension reynolds number is an important parameter in the equations that describe whether flow conditions lead to this flow. The common application of laminar flow would be in the smooth flow of viscous liquid through a tube or pipe. In that case, the velocity of flow varies from zero at the walls to a maximum along the centerline of the vessel.


TURBULENT FLOW This flow occurs when the reynolds number exceeds 4000. Eddy currents are present within the flow & the ratio of the internal roughness of the pipe to the internal diametre of the pipe needs to be considered to be able to determine the friction factor. In large diameter pipes the over all effect of the eddy currents is less significant.


UNIFORM FLOW. The depth average flow velocity, area of flow cross section are every where constant along t When the flow enters into a channel, the boundary layers grows up to free surface. FLOW changes from the uniform flow to critical flow in the transitory zone at exit in mid channel. The boundary layer as it grows along the channel at the entrance emerges to the free surface at a certain distance from the entry point .THIS zone is called ENTRY TRANSITION ZONE. If the bed slope is critical slope, then transitory zone in the entrance only exists.


The uniform flow extends till the flow terminates & exists as a jet at critical depth. This flow is known as CRITICAL UNIFORM FLOW. In the case of steep channel, the flow enters through a hydraulic drop or at uniform flow depth.


NON UNIFORM FLOW. The ubiquity of steady non uniform flow in in open channels establishes the need for con venient &accurate means of computation. Problems which arise frequently are determination of surface profile & depth discharge relationship .The first of these needs no comment .The second may be discussed in terms of the expression Q=(Y1,Y2) in which Q is the discharge, Y1 is the depth at the upstream end & Y2 the depth at the downstream end of a rich with more or less constant cross section & bed slope .


To find any of these relationship it is necessary to integrate the varied flow equation. This may be done by using a step by step arithmetical process, or by using tables of varied flow function in the methods of Bakhmeteff(1932) , von seggern ( 1949), Chow (1959). All of this require extensive arithmetical labour.The work is tedious & tiring .



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