Variational Multiscale Large Eddy Simulation of Turbulent Flow in a Diffuser

In the present study, variational multiscale large eddy simulation (LES) is applied to turbulent flow in a diffuser, which represents a challenging test case due to the appearance of flow separation and subsequent reattachment. Two different scale-separating operators based on multigrid operators are used for separating large and small resolved scales. Dynamic as well as constant-coefficient-based subgrid-scale modeling are employed in the variational multiscale LES. The results show that the variational multiscale LES with a simple constant-coefficient Smagorinsky model using a projective scale-separating operator yields a very good prediction of most of the crucial flow features. Furthermore, it turns out to be by far the most computationally efficient approach, resulting in a computing time reduction of about 18% compared to the traditional LES with a dynamic Smagorinsky model. The variational multiscale LES with a dynamic Smagorinsky model does not prove to be a superior approach.

[1]  Volker Gravemeier,et al.  The variational multiscale method for laminar and turbulent flow , 2006 .

[2]  K. Lilly.  The representation of small-scale turbulence in numerical simulation experiments , 1966 .

[3]  T. Hughes,et al.  Large Eddy Simulation and the variational multiscale method , 2000 .

[4]  John K. Eaton,et al.  Experimental investigation of flow through an asymmetric plane diffuser , 2000 .

[5]  S. Collis,et al.  Monitoring unresolved scales in multiscale turbulence modeling , 2001 .

[6]  P. Durbin.  SEPARATED FLOW COMPUTATIONS WITH THE K-E-V2 MODEL , 1995 .

[7]  T. Hughes,et al.  The variational multiscale formulation of LES - Channel Flow at Re(sub tau) = 590 , 2002 .

[8]  A. W. Vreman.  The filtering analog of the variational multiscale method in large-eddy simulation , 2003 .

[9]  K. Jansen,et al.  An evaluation of the variational multiscale model for large-eddy simulation while using a hierarchical basis , 2002 .

[10]  Parviz Moin,et al.  Study of flow in a planar asymmetric diffuser using large-eddy simulation , 1999, Journal of Fluid Mechanics.

[11]  Volker John,et al.  A Finite Element Variational Multiscale Method for the Navier-Stokes Equations , 2005, SIAM J. Sci. Comput..

[12]  Volker Gravemeier,et al.  Scale-separating operators for variational multiscale large eddy simulation of turbulent flows , 2006, J. Comput. Phys..

[13]  Charbel Farhat,et al.  A Variational Multiscale Method for the Large Eddy Simulation of Compressible Turbulent Flows on Unstructured Meshes - Application to vortex shedding , 2004 .

[14]  Thomas J. R. Hughes,et al.  The multiscale formulation of large eddy simulation: Decay of homogeneous isotropic turbulence , 2001 .

[15]  Ekkehard Ramm,et al.  Large eddy simulation of turbulent incompressible flows by a three‐level finite element method , 2005 .

[16]  Thomas J. R. Hughes,et al.  Large eddy simulation of turbulent channel flows by the variational multiscale method , 2001 .

[17]  P. Moin,et al.  A dynamic subgrid‐scale eddy viscosity model , 1990 .

[18]  Gianluca Iaccarino,et al.  Predictions of a turbulent separated flow using commercial CFD codes , 2001 .

[19]  S. Scott Collis,et al.  The DG/VMS Method for Unified Turbulence Simulation , 2002 .

[20]  Victor M. Calo,et al.  Residual-based multiscale turbulence modeling: Finite volume simulations of bypass transition , 2005 .

[21]  Leonhard Kleiser,et al.  Subgrid‐scale energy transfer in the near‐wall region of turbulent flows , 1994 .

[22]  Dongjoo Kim,et al.  A Second-Order Time-Accurate Finite Volume Method for Unsteady Incompressible Flow on Hybrid Unstructured Grids , 2000 .

[23]  Charbel Farhat,et al.  A dynamic variational multiscale method for large eddy simulations on unstructured meshes , 2006 .

[24]  Parviz Moin,et al.  Unstructured LES of Reacting Multiphase Flows in Realistic Gas Turbine Combustors , 2003 .

[25]  Thomas J. R. Hughes,et al.  Energy transfers and spectral eddy viscosity in large-eddy simulations of homogeneous isotropic turbulence: Comparison of dynamic Smagorinsky and multiscale models over a range of discretizations , 2004 .

[26]  John Kim,et al.  DIRECT NUMERICAL SIMULATION OF TURBULENT CHANNEL FLOWS UP TO RE=590 , 1999 .

[27]  David D. Apsley,et al.  Advanced Turbulence Modelling of Separated Flow in a Diffuser , 2000 .

[28]  G. Amberg,et al.  Numerical and experimental study of separated flow in a plane asymmetric diffuser , 2004 .

[29]  P. Moin,et al.  Computational study on the internal layer in a diffuser , 2005, Journal of Fluid Mechanics.

[30]  J. Smagorinsky,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS , 1963 .

[31]  P. Sagaut,et al.  A multilevel algorithm for large-Eddy simulation of turbulent compressible flows , 2001 .

[32]  J. Deardorff.  A numerical study of three-dimensional turbulent channel flow at large Reynolds numbers , 1970, Journal of Fluid Mechanics.

[33]  P. Moin,et al.  On the Effect of Numerical Errors in Large Eddy Simulations of Turbulent Flows , 1997 .

[34]  P. Moin,et al.  A numerical method for large-eddy simulation in complex geometries , 2004 .