Implementation of density-based solver for all speeds in the framework of OpenFOAM

Abstract

In the framework of open source CFD code OpenFOAM, a density-based solver for all speeds flow field is developed. In this solver the preconditioned all speeds AUSM+(P) scheme is adopted and the dual time scheme is implemented to complete the unsteady process. Parallel computation could be implemented to accelerate the solving process. Different interface reconstruction algorithms are implemented, and their accuracy with respect to convection is compared. Three benchmark tests of lid-driven cavity flow, flow crossing over a bump, and flow over a forward-facing step are presented to show the accuracy of the AUSM+(P) solver for low-speed incompressible flow, transonic flow, and supersonic/hypersonic flow. Firstly, for the lid driven cavity flow, the computational results obtained by different interface reconstruction algorithms are compared. It is indicated that the one dimensional reconstruction scheme adopted in this solver possesses high accuracy and the solver developed in this paper can effectively catch the features of low incompressible flow. Then via the test cases regarding the flow crossing over bump and over forward step, the ability to capture characteristics of the transonic and supersonic/hypersonic flows are confirmed. The forward-facing step proves to be the most challenging for the preconditioned solvers with and without the dual time scheme. Nonetheless, the solvers described in this paper reproduce the main features of this flow, including the evolution of the initial transient. Program summaryProgram title: allSpeedUnsteadFoam/allSpeedUnsteadFoam_dualtimeCatalogue identifier: AETK_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETK_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU General Public LicenseNo. of lines in distributed program, including test data, etc.: 255467No. of bytes in distributed program, including test data, etc.: 971156Distribution format: tar.gzProgramming language: C++.Computer: All capable of running Linux.Operating system: Linux.Has the code been vectorized or parallelized?: Yes ParallelizedRAM: 500 MB or moreClassification: 12.External routines: OpenFOAM (http://www.openfoam.org)Nature of problem:This software provides a library of models for the simulation of steady and unsteady all speeds flow field (all Mach number flow field including incompressible and compressible flow). Combining this library with other libraries within OpenFOAM, such as turbulence, radiation, solid conduction, etc., the more complex multi-physics model including all speeds flow field could be established conveniently.Solution method:Standard finite volume method (FVM) is used for solving all the preconditioned conservation governing equations. The preconditioned all speeds AUSM+(P) scheme is adopted to discretize the convective term in the governing equations. The total variation diminishing (TVD) scheme with interface reconstruction is used to improve the accuracy of this solver. The dual time scheme is used to solve the unsteady problem.Restrictions:The limiter functions have obvious effect on the accuracy of the numerical result and according to actual situation, so the selection of limiter functions should be focused on.Running time:It can vary from minutes to days to weeks depending on the size of the system, length of time simulated and number of processors used.