# Nonlinear Effect in-flow in Porous Duct

Thesis

In general, it is assumed in some non viscous flows that the flow velocity is constant at a cross-section. In this thesis, If we impose more realistic boundary conditions by, for example, introducing viscosity,and suction at walls, the net mass flow will change since the continuity equation must hold. The convective acceleration terms will be products of variables such that a nonlinear behavior will take place in the flow. The work will consist of deriving all the equations and parameters needed to described this kind of flow.An approximate analytic solution for the case of small Reynold number Re is discussed.Expression for the velocity components and pressure are obtained.The governing nonlinear differential equation that cannot be solved analytically is solved numerically using Runge-Kutta Program and the graph of axial and radial velocity profiles have drawn.