Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Effects of Freestream Flow Conditions on the Convergence History for Transitional Flow Simulations
Submission Author:
Aline Righi , SP
Co-Authors:
Aline Righi, Gustavo Luiz Olichevis Halila, João Luiz F. Azevedo
Presenter: Gustavo Luiz Olichevis Halila
doi://10.26678/ABCM.COBEM2023.COB2023-1159
Abstract
The appropriate treatment of transition to turbulence remains a central challenge in Computational Fluid Dynamics (CFD). Although CFD simulations have been used in the design and development processes in the aerospace industry for quite some time now, the correct treatment of transitional flows over general configurations still needs some attention. The present work addresses the impact of mesh size and physical reference parameters in the residues convergence and transition front location, when considering high Reynolds number, transitional flows. The approach adopted here uses a Reynolds-averaged Navier-Stokes formulation, with the Shear Stress Transport (SST) model for turbulence closure, which is further coupled to the Langtry-Menter transition model. The SST turbulence model uses two equations of transport for turbulence closure, and the Langtry-Menter transition model uses two additional transport equations to predict the laminar-turbulent transition. The Langtry-Menter model is compatible with modern CFD techniques, such as unstructured grids and parallel processing. One main feature of transitional flows is that transition can be caused by a few different mechanisms. For example, transition can be triggered due to the amplification of Tollmien-Schlichting waves or bypass transition, and the Langtry-Menter transition model is capable of predicting both. In order to achieve the goals of the present work, the Langtry-Menter transition model is implemented in a local code that has been developed over the past years, called BRU3D. Two test cases are presented in this paper, a zero pressure gradient flat plate and the NLF(1)-0416 airfoil. For the flat plate, two different meshes, one coarse and one fine, are used in the simulations. For the NLF(1)-0416 airfoil geometry three meshes are used, one coarse, one fine, and one super fine. Also, the skin friction coefficient is used here for all cases in order to visualize the influence over the transition location due to the mesh size and physical reference values.
Keywords
CFD, Laminar-turbulent transition, Langtry-Menter model, Numerical Convergence
