Regime transition in the energy cascade of rotating turbulence
T. Pestana, S. Hickel (2019)
Phys. Rev. E 99, 053103. doi: 10.1103/PhysRevE.99.053103
Transition from a split to a forward kinetic energy cascade system is explored in the context of rotating turbulence using direct numerical simulations with a three-dimensional isotropic random force uncorrelated with the velocity field. Our parametric study covers confinement effects in high-aspect-ratio domains and a broad range of rotation rates.
Effectivity and efficiency of selective frequency damping for the computation of unstable steady-state solutions
J. Casacuberta, K.J. Groot, H.J. Tol, S. Hickel (2018)
Journal of Computational Physics 375: 481-497. doi: 10.1016/j.jcp.2018.08.056
Selective Frequency Damping (SFD) is a popular method for the computation of globally unstable steady-state solutions in fluid dynamics. The approach has two model parameters whose selection is generally unclear. In this article, a detailed analysis of the influence of these parameters is presented, answering several open questions with regard to the effectiveness, optimum efficiency and limitations of the method.
Turbulent flow through a high aspect ratio cooling duct with asymmetric wall heating
Kaller, T., Pasquariello, V., Hickel, S., Adams, N.A. (2019)
Journal of Fluid Mechanics 860: 258-299. doi: 10.1017/jfm.2018.836
We present well-resolved large-eddy simulations of turbulent flow through a straight, high aspect ratio cooling duct operated with water at a bulk Reynolds number of Reb = 110 000 and an average Nusselt number of Nu = 371. The geometry and boundary conditions follow an experimental reference case and good agreement with the experimental results is achieved.
Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A
J. Matheis, S. Hickel (2018)
International Journal of Multiphase Flow 99: 294-311. doi: 10.1016/j.ijmultiphaseflow.2017.11.001
We present and evaluate a two-phase model for Eulerian large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model is based on cubic equations of state and vapor-liquid equilibrium calculations and can represent the coexistence of supercritical states and multi-component subcritical two-phase states via a homogeneous mixture approach.
Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number
V. Pasquariello, S. Hickel, N.A. Adams (2017)
Journal of Fluid Mechanics 828: 617-657. doi: 10.1017/jfm.2017.308
We analyse the low-frequency dynamics of a high Reynolds number impinging shock-wave/turbulent boundary-layer interaction (SWBLI) with strong mean-flow separation. The flow configuration for our grid-converged large-eddy simulations (LES) reproduces recent experiments for the interaction of a Mach 3 turbulent boundary layer with an impinging shock that nominally deflects the incoming flow by 19.6° . The Reynolds number based on the incoming boundary-layer thickness of Reδ ≈ 203 000 is considerably higher than in previous LES studies.
Three-dimensional reacting shock-bubble interaction
F. Diegelmann, S. Hickel, N.A. Adams (2017)
Combustion and Flame 181: 1339-1351. doi: 10.1016/j.combustflame.2017.03.026
We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric H2-O2 gas mixture inside the bubble. We study the interaction between hydrodynamic instabilities and shock-induced reaction waves at a shock Mach number of Ma = 2.83.
Large-eddy simulation of turbulent, cavitating flow inside a 9-hole Diesel injector including needle movement
F. Örley, S. Hickel, S.J. Schmidt, N.A. Adams (2017)
International Journal of Engine Research 18:195-211. doi: 10.1177/1468087416643901
We investigate the turbulent multiphase flow inside a nine-hole common rail Diesel injector during a full injection cycle of ISO 4113 diesel fuel into air by implicit large-eddy simulation (LES). The simulation includes a prescribed needle movement obtained from a one-dimensional multi-domain simulation.
Multi-component vapor-liquid equilibrium model for LES and application to ECN Spray A
J. Matheis, S. Hickel (2016)
Proceedings of the 2016 Summer Program, Center for Turbulence Research, Stanford University. (also available online on arXiv:1609.08533)
We present and evaluate a detailed multi-species two-phase thermodynamic equilibrium model for large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model can represent the coexistence of supercritical states and multi-component subcritical two-phase states.
Large-eddy simulation of nitrogen injection at trans- and supercritical conditions
H. Müller, C. Niedermeier, J. Matheis, M. Pfitzner, S. Hickel (2016)
Physics of Fluids 28: 015102. doi: 10.1063/1.4937948
Large-eddy simulations (LES) of cryogenic nitrogen injection into a warm environment at supercritical pressure are performed and real-gas thermodynamics models and subgrid-scale (SGS) turbulence models are evaluated. The comparison of different SGS models — the Smagorinsky model, the Vreman model, and the adaptive local deconvolution method — shows that the representation of turbulence on the resolved scales has a notable effect on the location of jet break-up, whereas the particular modeling of unresolved scales is less important for the overall mean flow field evolution. More important are the models for the fluid’s thermodynamic state.
Shock Mach number influence on reaction wave types and mixing in reactive shock-bubble interaction
F. Diegelmann, S. Hickel, N.A. Adams (2016)
Combustion and Flame 174: 85-99. doi: 10.1016/j.combustflame.2016.09.014
We present numerical simulations for a reactive shock–bubble interaction with detailed chemistry. The convex shape of the bubble leads to shock focusing, which generates spots of high pressure and temperature. Pressure and temperature levels are sufficient to ignite the stoichiometric H2–O2 gas mixture. Shock Mach numbers between Ma = 2.13 and Ma = 2.90 induce different reaction wave types (deflagration and detonation).
On the pressure dependence of ignition and mixing in two-dimensional reactive shock-bubble interaction
F. Diegelmann, V. Tritschler, S. Hickel, N.A. Adams (2016)
Combustion and Flame 163:414-426. doi: 10.1016/j.combustflame.2015.10.016
We analyse results of numerical simulations of reactive shock-bubble interaction with detailed chemistry. The interaction of the Richtmyer–Meshkov instability and shock-induced ignition of a stoichiometric H2-O2 gas mixture is investigated. Different types of ignition (deflagration and detonation) are observed at the same shock Mach number of Ma = 2.30 upon varying initial pressure.
Efficient implicit LES method for the simulation of turbulent cavitating flows
C.P. Egerer, S.J. Schmidt, S. Hickel, N.A. Adams (2016)
Journal of Computational Physics 316: 453-469. doi: 10.1017/10.1016/j.jcp.2016.04.021
We present a numerical method for efficient large-eddy simulation of compressible liquid flows with cavitation based on an implicit subgrid-scale model. Phase change and subgrid-scale interface structures are modeled by a homogeneous mixture model that assumes local thermodynamic equilibrium. Unlike previous approaches, emphasis is placed on operating on a small stencil (at most four cells).
A cut-cell finite volume-finite element coupling approach for fluid-structure interaction in compressible flow
V. Pasquariello, G. Hammerl, F. Örley, S. Hickel, C. Danowski, A. Popp, W.A. Wall, N.A. Adams (2016)
Journal of Computational Physics 307: 670-695. doi: 10.1016/j.jcp.2015.12.013
We present a loosely coupled approach for the solution of fluid–structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet–Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface.
Volume translation methods for real-gas computational fluid dynamics simulations
J. Matheis, H. Müller, C. Lenz, M. Pfitzner, S. Hickel (2016)
Journal of Supercritical Fluids 107: 422-432.
doi: 10.1016/j.supflu.2015.10.004
We report on recent developments within the field of real gas thermodynamics models with particular emphasis on volume translation methods for cubic equations of state. On the basis of the generalized form of a cubic equation of state, a mathematical framework for applying volume translations is provided, allowing for an unified and thermodynamically consistent formulation in the context of computational fluid dynamics simulations.
Large-eddy simulation of coaxial LN2/GH2 injection at trans- and supercritical conditions
H. Müller, M. Pfitzner, J. Matheis, S. Hickel (2015)
Journal of Propulsion and Power 32: 46-56. doi: 10.2514/1.B35827
Large-eddy simulations are carried out for the coaxial injection of liquid nitrogen and preheated hydrogen at supercritical pressures. A novel volume-translation method on the basis of the cubic Peng–Robinson equation of state is introduced for the use in multispecies large-eddy simulations and is tested for both trans- and supercritical injection conditions.
Validation of large-eddy simulation methods for gravity wave breaking
S. Remmler, S. Hickel, M.D. Fruman, U. Achatz (2015)
Journal of the Atmospheric Sciences 72: 3537-3562. doi: 10.1175/JAS-D-14-0321.1
To reduce the computational costs of numerical studies of gravity wave breaking in the atmosphere, the grid resolution has to be reduced as much as possible. Insufficient resolution of small-scale turbulence demands a proper turbulence parameterization in the framework of a large-eddy simulation (LES). We consider three different LES methods—the adaptive local deconvolution method (ALDM), the dynamic Smagorinsky method (DSM), and a naïve central discretization without turbulence parameterization (CDS4)—for three different cases of the breaking of well-defined monochromatic gravity waves.