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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 16 Jun 2024 22:10:52 GMT2024-06-16T22:10:52ZStudy on the Resolution of Large-Eddy Simulations for Supersonic Jet Flows
http://hdl.handle.net/10985/22736
Study on the Resolution of Large-Eddy Simulations for Supersonic Jet Flows
JUNQUEIRA-JUNIOR, Carlos; F. ABREU, Diego; T. V. DAURICIO, Eron; F. AZEVEDO, João Luiz
The present study is concerned with large-eddy simulations (LES) of supersonic jet flows. The work addresses, in particular, the simulation of a perfectly expanded free jet flow with an exit Mach number of 1.4 and an exit temperature equal to the ambient temperature. Calculations are performed using a nodal discontinuous Galerkin method. The present effort studies the effects of mesh and polynomial refinement on the solution. The present calculations consider computational meshes and polynomial orders such that the number of degrees of freedom (DOFs) in the solution ranges from 50 to 410 million. Mean velocity results and root mean square (RMS) values of velocity fluctuations indicate a better agreement with experimental data as the resolution is increased. The generated data provide a good understanding of the effects of increasing the discretization refinement for LES calculations of jet flows. The present results can guide future simulations of similar flow configurations.
Wed, 01 Jun 2022 00:00:00 GMThttp://hdl.handle.net/10985/227362022-06-01T00:00:00ZJUNQUEIRA-JUNIOR, CarlosF. ABREU, DiegoT. V. DAURICIO, EronF. AZEVEDO, João LuizThe present study is concerned with large-eddy simulations (LES) of supersonic jet flows. The work addresses, in particular, the simulation of a perfectly expanded free jet flow with an exit Mach number of 1.4 and an exit temperature equal to the ambient temperature. Calculations are performed using a nodal discontinuous Galerkin method. The present effort studies the effects of mesh and polynomial refinement on the solution. The present calculations consider computational meshes and polynomial orders such that the number of degrees of freedom (DOFs) in the solution ranges from 50 to 410 million. Mean velocity results and root mean square (RMS) values of velocity fluctuations indicate a better agreement with experimental data as the resolution is increased. The generated data provide a good understanding of the effects of increasing the discretization refinement for LES calculations of jet flows. The present results can guide future simulations of similar flow configurations.A comparison of low and high-order methods for the simulation of supersonic jet flows
http://hdl.handle.net/10985/22656
A comparison of low and high-order methods for the simulation of supersonic jet flows
F. ABREU, Diego; T. V. DAURICIO, Eron; F. AZEVEDO, João Luiz; JUNQUEIRA-JUNIOR, Carlos
The present work compares results for different numerical methods in search of alternatives to improve the quality
of large-eddy simulations for the problem of a supersonic turbulent jet flows. Previous work has analyzed supersonic
jet flows using a second-order, finite difference solver based on structured meshes, and the results indicated a shorter
potential core of the jet and different levels of velocity fluctuations. In the present work, the results of previous simulations
are compared to new results using a high-order, discontinuous Galerkin solver for unstructured meshes. All simulations
are performed, keeping the total number of degrees of freedom constant. The results of the current simulations present very
similar mean velocity distributions and slightly smaller velocity fluctuations, and they seem to correlate better with the
experimental data. The present results indicate that additional studies should focus on the jet inlet boundary conditions
in order to improve the physical representation of the early stages of the jet development.
Mon, 01 Nov 2021 00:00:00 GMThttp://hdl.handle.net/10985/226562021-11-01T00:00:00ZF. ABREU, DiegoT. V. DAURICIO, EronF. AZEVEDO, João LuizJUNQUEIRA-JUNIOR, CarlosThe present work compares results for different numerical methods in search of alternatives to improve the quality
of large-eddy simulations for the problem of a supersonic turbulent jet flows. Previous work has analyzed supersonic
jet flows using a second-order, finite difference solver based on structured meshes, and the results indicated a shorter
potential core of the jet and different levels of velocity fluctuations. In the present work, the results of previous simulations
are compared to new results using a high-order, discontinuous Galerkin solver for unstructured meshes. All simulations
are performed, keeping the total number of degrees of freedom constant. The results of the current simulations present very
similar mean velocity distributions and slightly smaller velocity fluctuations, and they seem to correlate better with the
experimental data. The present results indicate that additional studies should focus on the jet inlet boundary conditions
in order to improve the physical representation of the early stages of the jet development.Large-eddy simulations of turbulent compressible supersonic jet flows using discontinuous Galerkin methods
http://hdl.handle.net/10985/23681
Large-eddy simulations of turbulent compressible supersonic jet flows using discontinuous Galerkin methods
F. ABREU, Diego; JUNQUEIRA JUNIOR, Carlos; DAURICIO, Eron; F. AZEVEDO, João Luiz
In this work, a discontinuous Galerkin scheme is employed to perform the simulations of supersonic jet flows. A total of four simulations are performed with different meshes and order of accuracy. The number of degrees of freedom from the simulations varies from 50 × 10^6 to 400 × 10^6. The results indicate that by increasing the resolution of simulation, in general, the results got closer to experimental data. The jet lipline is the only region in which this behavior is not observed. It investigated a procedure of using lower-order simulations to initialize high-order simulations and consequently reduce the total time of the simulation using high-order schemes. This strategy is successful and allows to perform high-order simulations with only 5% more computational effort than a complete second-order simulation.
Wed, 01 Jun 2022 00:00:00 GMThttp://hdl.handle.net/10985/236812022-06-01T00:00:00ZF. ABREU, DiegoJUNQUEIRA JUNIOR, CarlosDAURICIO, EronF. AZEVEDO, João LuizIn this work, a discontinuous Galerkin scheme is employed to perform the simulations of supersonic jet flows. A total of four simulations are performed with different meshes and order of accuracy. The number of degrees of freedom from the simulations varies from 50 × 10^6 to 400 × 10^6. The results indicate that by increasing the resolution of simulation, in general, the results got closer to experimental data. The jet lipline is the only region in which this behavior is not observed. It investigated a procedure of using lower-order simulations to initialize high-order simulations and consequently reduce the total time of the simulation using high-order schemes. This strategy is successful and allows to perform high-order simulations with only 5% more computational effort than a complete second-order simulation.