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COBEM 2021
26th International Congress of Mechanical Engineering
A Comparison of Low and High-Order Methods for the Simulation of Supersonic Jet Flows
Submission Author:
Diego Ferolla de Abreu , SP
Co-Authors:
Diego Ferolla de Abreu, Carlos JUNQUEIRA-JUNIOR, Eron Tiago Viana Dauricio, João Luiz F. Azevedo
Presenter: Diego Ferolla de Abreu
doi://10.26678/ABCM.COBEM2021.COB2021-0388
Abstract
The present work is concerned with large eddy simulations (LES) of supersonic jet flows. Previous work by some of the present authors has addressed such simulations with low-order methods. The present effort uses a discontinuous Galerkin (DG) based solver in order to revisit the problem and perform a detailed study of the effect of the use of high-order methods for jet flow simulations. LES calculations of jet flows can be relevant for many applications. In this particular case, the authors are interested in understanding some of the mixing mechanisms present in the jet development. The LES formulation here adopted is based on the filtered Navier Stokes equations with the Smagorinsky sub-grid scale (SGS) model. The high order solver implements the nodal discontinuous Galerkin approach, in which the solution is approximated by a polynomial interpolation using internal points with a Gauss-Lobatto distribution. The simulation is based on the experiment that analyzed the jet flow emerging from an adjusted convergent-divergent nozzle. The jet exit Mach number is 1.4 and the Reynolds number, calculated as a function of the jet exit speed, is 1.5x106. All simulations use a similar number of degrees of freedom (DOFs). The present calculations with the DG solver are compared with experimental data and the results presented in previous work that has used a low-order finite difference method. The results for the time averaged velocity components at several planes downstream of the jet exit, as well as those for the mean velocity and pressure distributions along the centerline and the lip line of the jet, are used for the assessment of the present calculations. Similarly, RMS values of the fluctuating part of the velocity components are also used for the understanding and evaluation of the present results. The results obtained so far indicate that the present calculations using a low-order (2nd-order) DG method are more dissipative than the results using the low-order finite difference scheme, for the same number of DOFs. On the other hand, the use of a 3rd-order DG scheme yields better results than those obtained in the previous simulations. The final paper will present the formulation of the methods and a detailed analysis of the simulation results.
Keywords
Jet flows, Large Eddy Simulation, Discontinuous Galerkin
