Spectral structure of stratified turbulence: Direct Numerical Simulations and predictions by Large Eddy Simulation
S. Remmler, S. Hickel (2013)
Theoretical and Computational Fluid Dynamics 27: 319-336. doi: 10.1007/s00162-012-0259-9
Density stratification has a strong impact on turbulence in geophysical flows. Stratification changes the spatial turbulence spectrum and the energy transport and conversion within the spectrum. We analyze these effects based on a series of direct numerical simulations (DNS) of stratified turbulence.
Implicit Large Eddy Simulation of cavitation in micro channel flows
S. Hickel, M. Mihatsch, S.J. Schmidt (2011)
In proceedings of the WIMRC 3rd International Cavitation Forum ; Warwick, UK.; ISBN 978-0-9570404-1-0. arXiv: 1401.6548
We present a numerical method for Large Eddy Simulations (LES) of compressible two-phase flows. The method is validated for the flow in a micro channel with a step-like restriction. This setup is representative for typical cavitating multi-phase flows in fuel injectors and follows an experimental study of Iben et al. (2010).
Large Eddy Simulation of turbulence enhancement due to forced shock motion in shock boundary layer interaction
O.C. Petrache, S. Hickel, N.A. Adams (2011)
AIAA paper 2011-2216. doi: 10.2514/6.2011-2216
We present Implicit Large-Eddy Simulations of a shockwave-turbulent boundary layer interaction with and without localized heat addition. For an entropy spot generated ahead of the shock, baroclinic vorticity production occurs when the resulting density peak passes the shock.
Integrated experimental-numerical analysis of high agility aircraft wake vortex evolution
J.-U. Klar, C. Breitsamter, S. Hickel, N.A. Adams (2011)
Journal of Aircraft 48: 2050-2058. doi: 10.2514/1.C031438
The presented investigation includes a combined experimental–numerical approach to quantify the wake vortex system of a high-agility aircraft from the near field up to the far field.
Wall modeling for implicit large-eddy simulation and immersed-interface methods
Z.L. Chen, S. Hickel, A. Devesa, J. Berland, N.A. Adams (2013)
Theoretical and Computational Fluid Dynamics 28: 1-21. doi: 10.1007/s00162-012-0286-6
We propose and analyze a wall model based on the turbulent boundary layer equations (TBLE) for implicit large-eddy simulation (LES) of high Reynolds number wall-bounded flows in conjunction with a conservative immersed-interface method for mapping complex boundaries onto Cartesian meshes. Both implicit subgrid-scale model and immersed-interface treatment of boundaries offer high computational efficiency for complex flow configurations.
A conservative immersed interface method for large-eddy simulation of incompressible flows
M. Meyer, A. Devesa, S. Hickel, X.Y. Hu, N.A. Adams (2010)
Journal of Computational Physics 229: 6300-6317. doi: 10.1016/j.jcp.2010.04.040
We propose a conservative, second-order accurate immersed interface method for representing incompressible fluid flows over complex three dimensional solid obstacles on a staggered Cartesian grid. The method is based on a finite-volume discretization of the incompressible Navier–Stokes equations which is modified locally in cells that are cut by the interface in such a way that accuracy and conservativity are maintained.
Assessment of implicit large-eddy simulation with a conservative immersed interface method for turbulent cylinder flow
M. Meyer, S. Hickel, N.A. Adams (2010)
International Journal of Heat and Fluid Flow 31: 368-377. doi: 10.1016/j.ijheatfluidflow.2010.02.026
The success of Large-Eddy Simulations (LES) of wall-bounded turbulence depends strongly on an accurate representation of the flow near the boundaries. Since in implicit LES the truncation error of the numerical discretization itself functions as SGS model, the order of accuracy of the discretization should be maintained near the boundary. In this paper, we analyze the performance of implicit LES for predicting turbulent flows along complex geometries.
On the evolution of dissipation rate and resolved kinetic energy in ALDM simulations of the Taylor-Green flow
S. Hickel, N.A. Adams, J.A. Domaradzki (2010)
Journal of Computational Physics 229: 2422-2423. doi: 10.1016/j.jcp.2009.11.017
We correct a data processing error in the article “Construction of explicit and implicit dynamic finite difference schemes and application to the large-eddy simulation of the Taylor–Green vortex” by Dieter Fauconnier, Chris De Langhe and Erik Dick published in the Journal of Computational Physics 228 (2009), pp. 8053–8084.
An adaptive local deconvolution model for compressible turbulence
S. Hickel, J. Larsson (2008)
Proceedings of the 2008 Summer Program, Center for Turbulence Research, Stanford University.
The objective of this project was the analysis and the control of local truncation errors in large eddy simulations. We show that physical reasoning can be incorporated into the design of discretization schemes. Using systematic procedures, a non-linear discretization method is developed where numerical and turbulence-theoretical modeling are fully merged. The truncation error itself functions as an implicit turbulence model which accurately represents the effects of unresolved turbulence.
Implicit LES applied to zero-pressure-gradient and adverse-pressure-gradient boundary-layer turbulence
S. Hickel, N.A. Adams (2008)
International Journal of Heat and Fluid Flow 29: 626-639. doi: 10.1016/j.ijheatfluidflow.2008.03.008
Well resolved large-eddy simulations (LES) of a fully turbulent flat-plate boundary-layer flow subjected to a constant adverse pressure gradient are conducted. Flow parameters are adapted to an available experiment. The Reynolds number based on the local free-stream velocity and momentum thickness is 670 at the inflow and 5100 at the separation point. Clauser’s pressure-gradient parameter increases monotonically from 0 up to approximately 100 since a constant pressure gradient is prescribed. The adverse pressure gradient leads to a highly unsteady and massive separation of the boundary layer. The numerical predictions agree well with theory and experimental data.
Implicit large-eddy simulation applied to turbulent channel flow with periodic constrictions
S. Hickel, T. Kempe, N.A. Adams (2008)
Theoretical and Computational Fluid Dynamics 22: 227-242. doi: 10.1007/s00162-007-0069-7
The subgrid-scale (SGS) model in a large-eddy simulation (LES) operates on a range of scales which is marginally resolved by discretization schemes. Accordingly, the discretization scheme and the subgrid-scale model are linked. One can exploit this link by developing discretization methods from subgrid-scale models, or the converse. Approaches where SGS models and numerical discretizations are fully merged are called implicit LES (ILES).
Analysis of truncation errors and design of physically optimized discretizations
S. Hickel, N.A. Adams (2008)
Quality and Reliability of Large-Eddy Simulations, Springer. doi: 10.1007/978-1-4020-8578-9_4
Further development of Large Eddy Simulation (LES) faces as major obstacle the strong coupling between subgrid-scale (SGS) model and the truncation error of the numerical discretization. Recent analyzes indicate that for certain discretizations and certain flow configurations the truncation error itself can act as implicit SGS model. In this paper, we explore how implicit SGS models can be derived systematically and propose a procedure for design, analysis, and optimization of nonlinear discretizations.
On implicit subgrid-scale modeling in wall-bounded flows
S. Hickel, N.A. Adams (2007)
Physics of Fluids 19: 105106. doi: 10.1063/1.2773765
Approaches to large eddy simulation where subgrid-scale model and numerical discretization are fully merged are called implicit large eddy simulation (ILES). Recently, we have proposed a systematic framework for development, analysis, and optimization of nonlinear discretization schemes for ILES [Hickel et al., J. Comput. Phys. 213, 413(2006)]. The resulting adaptive local deconvolution method (ALDM) provides a truncation error which acts as a subgrid-scale model consistent with asymptotic turbulence theory. In the present paper ALDM is applied to incompressible, turbulent channel flow to analyze the implicit model for wall-bounded turbulence.
Implicit subgrid-scale modeling for large-eddy simulation of passive-scalar mixing
S. Hickel, N.A. Adams, N.N. Mansour (2007)
Physics of Fluids 19: 095102. doi: 10.1063/1.2770522
Further development of large-eddy simulation (LES) faces as major obstacles the strong coupling between subgrid-scale (SGS) modeling and the truncation error of the numerical discretization. One can exploit this link by developing discretization methods where the truncation error itself functions as an implicit SGS model. The name “implicit LES” is used for approaches that merge the SGS model and numerical discretization.
Towards implicit subgrid-scale modeling by particle methods
S. Hickel, L. Weynans, N.A. Adams, G.-H. Cottet (2007)
European Series in Applied and Industrial Mathematics 16: 77-88. doi: 10.1051/proc:2007014
The numerical truncation error of vortex-in-cell methods is analyzed a-posteriori through the effective spectral numerical viscosity for simulations of three-dimensional isotropic turbulence. The interpolation kernels used for velocity-smoothing and re-meshing are identified as the most relevant components affecting the shape of the spectral numerical viscosity as a function of wave number.
A proposed simplification of the adaptive local deconvolution method
S. Hickel, N.A. Adams (2006)
European Series in Applied and Industrial Mathematics 16: 66-76. doi: 10.1051/proc:2007008
The adaptive local deconvolution method (ALDM) [Hickel, Adams and Domaradzki. J. Comp. Phys., 213:413436, 2006] provides a systematic framework for the implicit large-eddy simulation (ILES) of turbulent flows. Subject of the present paper is a modification of the numerical algorithm that allows for reducing the amount of computational operations without affecting the quality of the results.