TJ580 : Investigation of the power preconditioning method for improving the convergence of numerical simulation of unsteady turbulent flows
Thesis > Central Library of Shahrood University > Mechanical Engineering > MSc > 2018
Authors:
Mohammad Amin Shahnazi [Author], Pooria Akbarzadeh[Supervisor]
Abstarct: According to increasing industrial and engineering use of turbulent flows and placement of the flows in turbo machines, fluid transfer in pipes, heat exchangers, combustion engines, the atmosphere and the oceans and etc. in this particular category of flows, it is more necessary to analyze, study and model this type of the flow than before. In the this study, for the first time, the locally power-law preconditioning method for analyzing steady and unsteady incompressible turbulent flows around airfoils in high Reynolds numbers is utilized. In this method, the governing equations are modified by altering the time derivatives terms. The governing equations are discretized by the numerical method derived from the cell-centered Jameson’s finite volume algorithm. In addition, for solving the unsteady flows, an implicit dual-time procedure and for simulating the turbulent flows, Baldwin and Lomax algebraic model have been employed. The computations are presented for steady and unsteady turbulent flows around NACA0012 and ONERA-A airfoils at various angles of attack and Reynolds number. Results presented in this study focus on the velocity, pressure and eddy viscosity profiles, distribution of pressure coefficient, lift and drag coefficients and the effect of the power-law preconditioning method on the convergence rate. The numerical solution indicates an acceptable accuracy with the aid of the power-law preconditioning method in both steady and unsteady turbulent flows for high Reynolds numbers. Moreover, using the power-law preconditioning method improves the convergence speed significantly and reduces the iteration number of solution steps and time simultaneously in both steady and unsteady flows.
Keywords:
#Incompressible steady and unsteady Turbulent flow #Power-law preconditioning method #NACA0012 and ONERA_A airfoils #Baldwin and Lomax algebraic model. Link
Keeping place: Central Library of Shahrood University
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