GPU-accelerated simulations for eVTOL aerodynamic analysis
Pasquariello, V., Bunk, Y., Eberhardt, S., Huang, P.-H., Matheis, J., Ugolotti, M., Hickel, S. (2023)
AIAA Scitech paper 2023-2107. doi: 10.2514/6.2023-2107
The demand for fast, high-fidelity, scale-resolving computational fluid dynamics (CFD) simulations is continuously growing. Especially new emerging aviation technologies, such as electrical vertical take-off and landing aircraft (eVTOL), strongly rely on advanced numerical methods to retain development life-cycle costs and achieving design targets more quickly. This paper presents a cutting-edge large-eddy simulations (LES) solver developed to enable over-night turnaround times for full aircraft simulations on advanced graphics processing unit (GPU) architectures.
Verification and Validation of Immersed Boundary Solvers for Hypersonic Flows with Gas-Surface Interaction
Baskaya, A.O., Capriati, M., Ninni, D., Bonelli, F., Pascazio, G., Turchi, A., Magin T., Hickel, S. (2022)
AIAA Aviation Forum, Chicago. AIAA paper 2022-3276. doi: 10.2514/6.2022-3276
Verification and validation results of two immersed boundary solvers, INCA and CHESS, for atmospheric entry flows characterized by complex fluid thermochemistry and gas-surface interactions (GSI) are presented. Results are compared with those obtained with the body-conforming solver US3D, which is coupled to the same external thermochemistry library, Mutation++, as INCA and CHESS. In these campaigns, the INCA solver has shown an almost perfect agreement with the body-conforming reference solver and other reference results from literature.
Adaptive reduced-order modeling for non-linear fluid-structure interaction
Thari, A., Pasquariello, V., Aage, N., Hickel, S. (2021)
Computers and Fluids 229: 105099. doi: 10.1016/j.compfluid.2021.105099
We present an adaptive reduced-order model for the efficient time-resolved simulation of fluid–structure interaction problems with complex and non-linear deformations. The model is based on repeated linearizations of the structural balance equations. Upon each linearization step, the number of unknowns is strongly decreased by using modal reduction, which leads to a substantial gain in computational efficiency.
Large-eddy simulation of turbulent, cavitating flow inside a 9-hole Diesel injector including needle movement
Örley, F., Hickel, S., Schmidt, S.J., Adams, N.A. (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.
A cut-cell finite volume-finite element coupling approach for fluid-structure interaction in compressible flow
Pasquariello, V., Hammerl, G., Örley, F., Hickel, S., Danowski, C., Popp, A., Wall, W.A., Adams, N.A. (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.
Cut-element based immersed boundary method for moving geometries in compressible liquid flows with cavitation
Örley, F., Pasquariello, V., Hickel, S., Adams, N.A. (2015)
Journal of Computational Physics 283: 1-22. doi: 10.1016/j.jcp.2014.11.028
The conservative immersed interface method for representing complex immersed solid boundaries or phase interfaces on Cartesian grids is improved and extended to allow for the simulation of weakly compressible fluid flows through moving geometries. We demonstrate that an approximation of moving interfaces by a level-set field results in unphysical oscillations in the vicinity of sharp corners when dealing with weakly compressible fluids such as water. By introducing an exact reconstruction of the cut-cell properties directly based on a surface triangulation of the immersed boundary, we are able to recover the correct flow evolution free of numerical artifacts.
Wall-modelled Implicit Large-Eddy Simulation of the RA16SC1 Highlift Configuration
Meyer, M., Hickel, S., Breitsamter, C., Adams, N.A. (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.
An innovative approach to thermo-fluid-structure interaction based on an immersed interface method and a monolithic thermo-structure interaction algorithm
Grilli, M., Hickel, S., Adams, N.A., Hammerl, G., Danowski, C., Wall, W.A. (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.
Numerical modelling and investigation of symmetric and asymmetric cavitation bubble dynamics
Lauer, E., Hu, X.Y., Hickel, S., Adams, N.A. (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.
Numerical investigation of collapsing cavity arrays
Lauer, E., Hu, X.Y., Hickel, S., Adams, N.A. (2012)
Physics of Fluids 24: 052104. doi: 10.1063/1.4719142
Implicit Large Eddy Simulation of cavitation in micro channel flows
Hickel, S., Mihatsch, M., Schmidt S.J. (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).
Wall modeling for implicit large-eddy simulation and immersed-interface methods
Chen, Z.L., Hickel, S., Devesa, A., Berland, J., Adams, N.A. (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
Meyer, M., Devesa, A., Hickel, S., Hu, X.Y., Adams, N.A. (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
Meyer, M., Hickel, S., Adams, N.A. (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.
Implicit large-eddy simulation applied to turbulent channel flow with periodic constrictions
Hickel, S., Kempe, T., Adams, N.A. (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).