INCA - Computational Fluid Dynamics as good as it gets.

S. Remmler, M.D. Fruman, S. Hickel (2013)
Journal of Fluid Mechanics 722: 424-436. doi: 10.1017/jfm.2013.108

We have performed fully resolved three-dimensional numerical simulations of a statically unstable monochromatic inertia–gravity wave using the Boussinesq equations on an f - plane with constant stratification. The chosen parameters represent a gravity wave with almost vertical direction of propagation and a wavelength of 3 km breaking in the middle atmosphere.

Results of a large-eddy simulation (LES) of a supersonic turbulent boundary layer flow along a compression–expansion ramp configuration are presented. The numerical simulation is directly compared with an available experiment at the same flow conditions. The compression–expansion ramp has a deflection angle of β = 25°, the free-stream Mach number is Ma_∞ = 2.88, and the Reynolds number based on the incoming boundary layer thickness is Re_δ = 132 840 ${Re}_{δ_{0}} = 132840$ .

F. Rieper, S. Hickel, U. Achatz (2013)
Monthly Weather Review 141: 861-886. doi: 10.1175/MWR-D-12-00026.1

Durran’s pseudo-incompressible equations are integrated in a mass and momentum conserving way with a new implicit turbulence model. This system is soundproof, which has two major advantages over fully compressible systems: the Courant–Friedrichs–Lewy (CFL) condition for stable time advancement is no longer dictated by the speed of sound and all waves in the model are clearly gravity waves (GW).

M. Meyer, S. Hickel, C. Breitsamter, N.A. Adams (2013)
AIAA paper 2013-3037. doi: 10.2514/6.2013-3037

Industrially applied Computational Fluid Dynamics still faces a challenge when it comes to the accurate prediction of the complex flow over realistic highlift configurations. In this paper we demonstrate that the flow over the 3-element RA16SC1 highlift configuration can be efficiently and accurately predicted with Implicit Large-Eddy Simulation (ILES) on Cartesian adaptive grids.

M. Grilli, S. Hickel, N.A. Adams, G. Hammerl, C. Danowski, W.A. Wall (2012)
AIAA paper 2012-3267. doi: 10.2514/6.2012-3267

We present a loosely-coupled approach for the solution of the thermo-fluid-structure interaction problem, based on Dirichlet-Neumann partitioning. A Cartesian grid finite volume scheme, with conservative interface method is used for the fluid and a finite-element scheme for the thermo-structure problem. Special attention is given to the transfer of forces, temperatures and to the structural positions.

M. Grilli, L.S. Chen, S. Hickel, N.A. Adams, S. Willems, A. Gülhan (2012)
AIAA paper 2012-2701. doi: 10.2514/6.2012-2701

We report on an experimental and computational effort to study the interaction of a compressible turbulent boundary layer with an oblique shock wave. A wide range of shock intensities has been considered in the experiments through a variation of the free-stream Mach number.

E. Lauer, X.Y. Hu, S. Hickel, N.A. Adams (2012)
Computers and Fluids 69: 1-19. doi: 10.1016/j.compfluid.2012.07.020

In this paper, we investigate the high-speed dynamics of symmetric and asymmetric cavitation bubble-collapse. For this purpose, a sharp-interface numerical model is employed, that includes a numerically efficient evaporation/condensation model.

S. Hickel, E. Touber, J. Bodart, J. Larsson (2012)
Proceedings of the 2012 Summer Program, Center for Turbulence Research, Stanford University.

Wall-models are essential for enabling large-eddy simulations of realistic problems at high Reynolds numbers. The present study is focused on approaches that directly model the wall shear stress, specifically on filling the gap between models based on wall-normal ordinary differential equations (ODEs) that assume equilibrium and models based on full partial differential equations that do not. We develop ideas for how to incorporate non-equilibrium effects (most importantly, strong pressure-gradient effects) in the wall- model while still solving only wall-normal ODEs.

Simulations of geophysical turbulent flows require a robust and accurate subgrid-scale turbulence modeling. To evaluate turbulence models for stably stratified flows, we performed direct numerical simulations (DNSs) of the transition of the three-dimensional Taylor–Green vortex and of homogeneous stratified turbulence with large-scale horizontal forcing.

E. Lauer, X.Y. Hu, S. Hickel, N.A. Adams (2012)
Physics of Fluids 24: 052104. doi: 10.1063/1.4719142

In most technical applications involving cavitation, vapor bubbles occur in clouds, and their collapse is affected by the interaction with neighboring bubbles. One approach to study the influence of these interactions is the investigation of the collapse of cavity arrays in water under shock wave loading. We describe in detail the collapse mechanisms during the collapse of a horizontal cavity array, with particular consideration of maximum pressures.

M. Grilli, P.J. Schmidt, S. Hickel, N.A. Adams (2012)
Journal of Fluid Mechanics 700: 16-28. doi: 10.1017/jfm.2012.37

The unsteady behaviour in shockwave turbulent boundary layer interaction is investigated by analysing results from a large eddy simulation of a supersonic turbulent boundary layer over a compression–expansion ramp. The flow dynamics are analysed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward–backward motion of the shock.

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.

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).

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.

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.

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.

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Direct numerical simulation of a breaking inertia-gravity wave

Large-eddy simulation of supersonic turbulent boundary layer over a compression-expansion ramp

A conservative integration of the pseudo-incompressible equations with implicit turbulence parameterization

Wall-modelled Implicit Large-Eddy Simulation of the RA16SC1 Highlift Configuration

An innovative approach to thermo-fluid-structure interaction based on an immersed interface method and a monolithic thermo-structure interaction algorithm

Experimental and numerical investigation on shockwave / turbulent boundary layer interaction

Numerical modelling and investigation of symmetric and asymmetric cavitation bubble dynamics

A parametrized non-equilibrium wall-model for large-eddy simulations

Direct and large-eddy simulation of stratified turbulence

Numerical investigation of collapsing cavity arrays

Analysis of unsteady behavior in shockwave turbulent boundary layer interaction

Spectral structure of stratified turbulence: Direct Numerical Simulations and predictions by Large Eddy Simulation

Implicit Large Eddy Simulation of cavitation in micro channel flows

Large Eddy Simulation of turbulence enhancement due to forced shock motion in shock boundary layer interaction

Integrated experimental-numerical analysis of high agility aircraft wake vortex evolution

Wall modeling for implicit large-eddy simulation and immersed-interface methods

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