Wall Friction Coefficient Research Articles

Laminar Flow in a Uniformly Porous Channel

Abstract The problem of laminar channel flow has been investigated for the case of uniform fluid suction or injection through the channel walls. The solution can be divided into three steps: (a) A judicious choice of stream function reduces the Navier-Stokes equations to an ordinary, fourth-order, nonlinear differential equation, which contains a free parameter R, the Reynolds number based upon fluid velocity through the wall. (b) Since general analysis of this equation is intractable, the parameter R is eliminated by a suitable transformation. (c) The transformed, nonparametric equation yields to a series solution, valid and absolutely convergent for all R. From this general solution, expressions are developed for velocity components, pressure distribution, and wall-friction coefficient.

Further Investigation of Laminar Flow in Channels with Porous Walls

The problem of two-dimensional steady-state laminar flow in channels with porous walls has been extended to the case of moderate to high suction or injection velocity at the walls. An exact solution of the Navier-Stokes equations, reduced to a third-order nonlinear differential equation with appropriate boundary conditions, is obtained. The velocity components, the pressure, and the coefficient of wall friction are expressed as functions of velocity through the porous walls, the average axial velocity of Poiseuille's flow, the coordinates and dimensions of the channel, and the physical properties of the fluid.