## Assessment of immersed boundary methods for hypersonic flows with gas–surface interactions

A.O. Başkaya, M. Capriati, A. Turchi, T. Magin, S. Hickel (2024)*Computers & Fluids* 270: 106134. doi: 10.1016/j.compfluid.2023.106134

The efficacy of immersed boundary (IB) methods with adaptive mesh refinement (AMR) techniques is assessed in the context of atmospheric entry applications, including effects of chemical nonequilibrium (CNE) and gas–surface interactions (GSI). We scrutinize a conservative cut-cell IB method and two non-conservative IB methods, comparing their results with analytical solutions, data from the literature, and results obtained with a reference solver that operates on body-fitted grids.

## Verification and Validation of Immersed Boundary Solvers for Hypersonic Flows with Gas-Surface Interaction

A.O. Başkaya, M. Capriati, D. Ninni, F. Bonelli, G. Pascazio, A. Turchi, T. Magin, S. Hickel (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.

## Assessment of RANS Turbulence Models for Straight Cooling Ducts: Secondary Flow and Strong Property Variation Effects

T. Kaller, A. Doehring, S. Hickel, S.J. Schmidt, N.A. Adams (2021) *Notes on Numerical Fluid Mechanics and Multidisciplinary Design* 146: 309-321. doi: 10.1007/978-3-030-53847-7_20

We present well-resolved RANS simulations of two generic asymmetrically heated cooling channel configurations, a high aspect ratio cooling duct operated with liquid water at Re_{b}=110 000 and a cryogenic transcritical channel operated with methane at Re_{b}=16 000.

## Prediction capability of RANS turbulence models for asymmetrically heated high-aspect-ratio duct flows

T. Kaller, S. Hickel, N.A. Adams (2020) *AIAA Scitech* paper 2020-0354. doi: 10.2514/6.2020-0354

We present well-resolved RANS simulations of a high-aspect-ratio generic cooling duct configuration consisting of an adiabatic straight feed line followed by a heated straight section ending with a 90° bend. The configuration is asymmetrically heated with a temperature difference of ∆T = 40 K. As fluid liquid water is used at a bulk Reynolds number of Re_{b} = 110 000.

## 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 Re_{b} = 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.

## Benchmarking in a rotating annulus: A comparative experimental and numerical study of baroclinic wave dynamics

M. Vincze, S. Borchert, U. Achatz, T. von Larcher, M. Baumann, C. Liersch, S. Remmler, T. Beck, K.D. Alexandrov, C. Egbers, J. Fröhlich, V. Heuveline, S. Hickel, U. Harlander (2015) *Meteorologische Zeitschrift* 23: 611-635. doi: 10.1127/metz/2014/0600

The differentially heated rotating annulus is a widely studied tabletop-size laboratory model of the general mid-latitude atmospheric circulation. The two most relevant factors of cyclogenesis, namely rotation and meridional temperature gradient are quite well captured in this simple arrangement. The radial temperature difference in the cylindrical tank and its rotation rate can be set so that the isothermal surfaces in the bulk tilt, leading to the formation of baroclinic waves.

## Finite-volume models with implicit subgrid-scale parameterization for the differentially heated rotating annulus

S. Borchert, U. Achatz, S. Remmler, S. Hickel, U. Harlander, M. Vincze, K.D. Alexandrov, F. Rieper, T. Heppelmann, S.I. Dolaptchiev (2014) *Meteorologische Zeitschrift* 23: 561-580. doi: 10.1127/metz/2014/0548

The differentially heated rotating annulus is a classical experiment for the investigation of baroclinic flows and can be regarded as a strongly simplified laboratory model of the atmosphere in mid-latitudes. Data of this experiment, measured at the BTU Cottbus-Senftenberg, are used to validate two numerical finite-volume models (INCA and cylFloit) which differ basically in their grid structure.

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

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.