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ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
NUMERICAL INFLUENCE OF VISCOUS FLUX CALCULATION SCHEMES FOR TURBULENT FLOW SIMULATIONS IN AERONAUTICAL APPLICATIONS
Submission Author:
Thamires das Chagas Silva , SP , Brazil
Co-Authors:
Thamires das Chagas Silva, Marco Aurélio Leonel Matunaga, Ricardo Galdino da SIlva, João Luiz F. Azevedo
Presenter: Thamires das Chagas Silva
doi://10.26678/ABCM.ENCIT2022.CIT22-0046
Abstract
The present work is part of an ongoing effort to provide continuous improvement to an in-house developed CFD solver, known as BRU3D. This code is currently being used to simulate turbulent flows over realistic aeronautical and aerospace configurations. The BRU3D code is a cell-centered, finite volume code that solves the 3-D Reynolds-averaged Navier-Stokes (RANS) equations, together with appropriate turbulence closure models, using unstructured meshes. An upwind spatial discretization is adopted, together with terms that ensure the satisfaction of an entropy inequality in the artifical dissipation terms, and it has an implicit time marching. For cell-centered methods, the schemes to constructing of the inviscid fluxes in the interface cells are well explored by the CFD community, such that robust schemes are reported by the literature. However, the construction of gradients for the calculation of viscous fluxes is a matter that still requires community attention. These schemes impact on numerical robustness and in the final result of the simulation. The emphasis of the present effort is in the analysis of the influence of two different schemes for the definition of viscous gradient values at cell interfaces in the turbulent flow simulations of interest to the institutions represented here. The simulations are performed for flows that present complex physical phenomena, such as interaction between shock wave and boundary layer, and cases which might exhibit separation of the flow, even at lower angles of attack, which address multiple element airfoils typical of high lift configurations. Therefore, after some initial validation for standard configurations, the paper will discuss results for transonic flow over the OAT15A airfoil and for high-lift flow over the McDonnell Douglas 30P30N multi-element airfoil. It will be seen that the influence of different schemes for the definition of viscous gradient values at cell interfaces is significant, demonstrating how much an accurate solution depends on numerical methods implemented in the code, not just the physics contained in the governing equations discretized by these methods. The final paper will present all the formulation details, as well as a thorough discussion of the simulation results.
Keywords
Computational Fluid Dynamics, turbulent flows, Navier-Stokes Equations, Flux Calculation Schemes
