[PDF] A Numerical Method For Computing Unsteady 2 D Boundary Layer Flows eBook

Author : National Aeronautics and Space Adm Nasa
Publisher : Independently Published
Page : 68 pages
File Size : 30,73 MB
Release : 2018-11-02
Category : Science
ISBN : 9781729465325

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A numerical method for computing unsteady two-dimensional boundary layers in incompressible laminar and turbulent flows is described and applied to a single airfoil changing its incidence angle in time. The solution procedure adopts a first order panel method with a simple wake model to solve for the inviscid part of the flow, and an implicit finite difference method for the viscous part of the flow. Both procedures integrate in time in a step-by-step fashion, in the course of which each step involves the solution of the elliptic Laplace equation and the solution of the parabolic boundary layer equations. The Reynolds shear stress term of the boundary layer equations is modeled by an algebraic eddy viscosity closure. The location of transition is predicted by an empirical data correlation originating from Michel. Since transition and turbulence modeling are key factors in the prediction of viscous flows, their accuracy will be of dominant influence to the overall results. Krainer, Andreas Unspecified Center...

Author : Charles Luh-Sun Farn
Publisher :
Page : 0 pages
File Size : 37,1 MB
Release : 1966
Category : Boundary layer
ISBN :

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A finite difference method for computing velocity and temperature profiles of an unsteady, incompressible, laminar boundary layer around a two-dimensional cylinder of arbitrary cross section is developed. Blowing or suction may be present on the wall of the cylinder. The thermal boundary condition at the wall may be either specified wall temperature or specified heat flux at the wall. The governing finite difference equations are explicit, the velocity and the temperature at the next time step can be directly computed in terms of those at the current time step. Various errors associated with the finite difference method are studied. Great effort has been made to derive the stability and convergence conditions of the method. The upper bound of the local rounding errors is estimated. Two examples, one oscillation in Blasius flow and the other impulsive start of wedge flow, are given; the numerical results are compared with the existing analytical and experimental results. It is concluded that the present method can be used for the aforementioned computation with high accuracy except at and near a singular point where the singular errors become significant. (Author).

Author : Vallampati Ramachandra Prasad
Publisher : BoD – Books on Demand
Page : 236 pages
File Size : 13,66 MB
Release : 2020-01-22
Category : Mathematics
ISBN : 1839681853

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Written by experts in the field, this book, "Boundary Layer Flows - Theory, Applications, and Numerical Methods" provides readers with the opportunity to explore its theoretical and experimental studies and their importance to the nonlinear theory of boundary layer flows, the theory of heat and mass transfer, and the dynamics of fluid. With the theory's importance for a wide variety of applications, applied mathematicians, scientists, and engineers - especially those in fluid dynamics - along with engineers of aeronautics, will undoubtedly welcome this authoritative, up-to-date book.