scholarly journals Locating a complex inhomogeneous medium with an approximate factorization method

2019 ◽  
Vol 35 (4) ◽  
pp. 045001 ◽  
Author(s):  
Fenglong Qu ◽  
Haiwen Zhang
Keyword(s):  
Inhomogeneous Medium ◽  
Factorization Method ◽  
Approximate Factorization

The factorization method for a cavity in an inhomogeneous medium

2014 ◽  
Vol 30 (4) ◽  
pp. 045008 ◽  
Author(s):  
Shixu Meng ◽  
Houssem Haddar ◽  
Fioralba Cakoni
Keyword(s):  
Inhomogeneous Medium ◽  
Factorization Method

Numerical Simulation of Viscous Flow-Field in Cascade Using Thin-Layer Equations and AF Method

1999 ◽  
Author(s):  
Yumin Xiao ◽  
R. S. Amano
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Viscous Flow ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Factorization Method ◽  
Computational Domain ◽  
Approximate Factorization ◽  
Calculation Results ◽  
Transonic Cascade

Abstract In this paper an implicit 3-D solver for computations of a viscous flow has been developed and the computations of the flow between blade passage are presented. This method employs an AF (Approximate Factorization) method in which four techniques are incorporated to speed up convergence to the steady-state solutions: (1) body-fitted H-grid; (2) artificial viscosity; (3) implicit residual smoothing; and (4) local time-stepping. The two-dimensional pseudo-characteristic method was used to determine the inlet and outlet boundary conditions of the computational domain and the periodic boundary conditions were used at inter-boards. The validation cases include subsonic and transonic viscous flows in C3X cascade. Results for these turbine cascade flows are presented and compared with experiments at corresponding conditions. Computed pressure distributions on blade surfaces show good agreement with the published experimental data. This method was further applied to a three-dimensional case and demonstrated the code capability for predicting the secondary flow in a 3-D transonic flow-field. From these computations it was found that the proposed method possesses superior convergence characteristics and can be extended to unsteady flow calculations. Finally, it was observed that the three-dimensional calculation results show that the secondary flow mechanism in a transonic cascade seems to be quit different from those, in a subsonic case.

Incompressible Navier-Stokes Computation of the NREL Airfoils Using a Symmetric Total Variational Diminishing Scheme

1994 ◽  
Vol 116 (4) ◽  
pp. 174-182 ◽  
Author(s):  
S. L. Yang ◽  
Y. L. Chang ◽  
O. Arici
Keyword(s):  
Turbulence Model ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Wind Tunnel Test ◽  
Factorization Method ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Approximate Factorization ◽  
Two Dimensional Flow ◽  
Good Agreement

The purpose of this paper is to present a numerical study of flow fields for the NREL S805 and S809 airfoils using a spatially second-order symmetric total variational diminishing scheme. The steady two-dimensional flow is modeled as turbulent, viscous, and incompressible and is formulated in the pseudo-compressible form. The turbulent flow is closed by the Baldwin-Lomax algebraic turbulence model. Numerical solutions are obtained by the implicit approximate-factorization method. The accuracy of the numerical results is compared with the Delft two-dimensional wind tunnel test data. For comparison, the Eppler code results are also included. Numerical solutions of pressure and lift coefficients show good agreement with the experimental data, but not the drag coefficients. To properly simulate the post-stall flow field, a better turbulence model should be used.

A Newton-Krylov Type Algorithm for an Incompressible Navier-Stokes Solver Using Pseudo Compressibility Technique

2010 ◽  
Author(s):  
Amir Nejat ◽  
Alireza Jalali ◽  
Mahkame Sharbatdar
Keyword(s):  
Krylov Subspace ◽  
Convergence Acceleration ◽  
Cavity Flow ◽  
Factorization Method ◽  
Navier Stokes ◽  
Approximate Factorization ◽  
Thomas Algorithm ◽  
Linear Solver ◽  
Type Algorithm

A Newton-Krylov type algorithm is designed and implemented for a pseudo compressible Navier-Stokes solver in an incompressible Cavity flow. Both GMRES and BICGSTAB (Krylov-subspace) techniques are employed for the solving the linear solver resulting from the residual linearization. ILU-0 and ILU-1 and Thomas algorithm are used for preconditioning. The results show promising convergence acceleration especially for the GMRES/ILU-1 case compared to the classic Approximate Factorization method.

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