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.
Secondary instabilities in swept-wing boundary layers: Direct Numerical Simulations and BiGlobal stability analysis
J. Casacuberta, K.J. Groot, S. Hickel, M. Kotsonis (2022)
SciTech Forum and Exposition, San Diego. AIAA paper 2022-2330, doi: 10.2514/6.2022-2330
The evolution of secondary instabilities in a three-dimensional stationary-crossflow-dominated boundary layer is investigated by means of Direct Numerical Simulations (DNS) and linear spanwise BiGlobal stability analysis. Single-frequency unsteady disturbances and a critical stationary crossflow mode are considered.
Experimental investigation of shock–shock interactions with variable inflow Mach number
L. Laguarda, J. Santiago Patterson, F.F.J. Schrijer, B.W. van Oudheusden, S. Hickel (2021)
Shock Waves 3: 457-468. doi: 10.1007/s00193-021-01029-3
Experiments on shock–shock interactions were conducted in a transonic–supersonic wind tunnel with variable free-stream Mach number functionality. Transition between the regular interaction (RI) and the Mach interaction (MI) was induced by variation of the free-steam Mach number for a fixed interaction geometry, as opposed to most previous studies where the shock generator angles are varied at constant Mach number.
Adaptive reduced-order modeling for non-linear fluid-structure interaction
A. Thari, V. Pasquariello, N. Aage, S. Hickel (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.
Towards adjoint-based mesh refinement for Large Eddy Simulation using reduced-order primal solutions: Preliminary 1D Burgers study
X. Li, S. Hulshoff, S. Hickel (2021)
Computer Methods in Applied Mechanics and Engineering 379: 113733. doi: 10.1016/j.cma.2021.113733
Adaptive Mesh Refinement (AMR) is potentially an effective way to automatically generate computational meshes for high-fidelity simulations such as Large Eddy Simulation (LES). When combined with adjoint methods, which are able to localize error contributions, AMR can generate meshes that are optimal for computing a physical quantity of interest (e.g. lift or drag).
Customized data-driven RANS closures for bi-fidelity LES–RANS optimization
Y. Zhang, R.P. Dwight, M. Schmelzer, J.F. Gómez, Z.-H. Han, S. Hickel (2021)
Journal of Computational Physics 432: 110153. doi: 10.1016/j.jcp.2021.110153
Multi-fidelity optimization methods promise a high-fidelity optimum at a cost only slightly greater than a low-fidelity optimization. This promise is seldom achieved in practice, due to the requirement that low- and high-fidelity models correlate well. In this article, we propose an efficient bi-fidelity shape optimization method for turbulent fluid-flow applications with Large-Eddy Simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) as the high- and low-fidelity models within a hierarchical-Kriging surrogate modelling framework.
Mechanisms of interaction between stationary crossflow instabilities and forward-facing steps
J. Casacuberta, S. Hickel, M. Kotsonis (2021)
AIAA Scitech paper 2021-0854. doi: 10.2514/6.2021-0854
We study the interaction between a stationary crossflow instability and forward-facing steps in a swept-wing boundary layer using Direct Numerical Simulations (DNS). The station- ary primary crossflow mode is imposed at the inflow. Steps of several heights are modeled.
Low-frequency unsteadiness mechanisms in shock wave/turbulent boundary layer interactions over a backward-facing step
W. Hu, S. Hickel, B.W. van Oudheusden (2021)
Journal of Fluid Mechanics 915: A107. doi: 10.1017/jfm.2021.95
The low-frequency unsteady motions behind a backward-facing step (BFS) in a turbulent flow at Ma=1.7 and Re∞=1.3718×107 m−1 are investigated using a well-resolved large-eddy simulation.
Rapid multi-component phase-split calculations using volume functions and reduction methods
M. Fathi, S. Hickel (2021)
AIChE Journal 67: e17174. doi: 10.1002/aic.17174
We present a new family of fast and robust methods for the calculation of the vapor–liquid equilibrium at isobaric-isothermal (PT-flash), isochoric-isothermal (VT-flash), isenthalpic-isobaric (HP-flash), and isoenergetic-isochoric (UV-flash) conditions. The framework is provided by formulating phase-equilibrium conditions for multi-component mixtures in an effectively reduced space based on the molar specific value of the recently introduced volume function derived from the Helmholtz free energy.
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 Reb=110 000 and a cryogenic transcritical channel operated with methane at Reb=16 000.
Inertia gravity waves breaking in the middle atmosphere: energy transfer and dissipation tensor anisotropy
T. Pestana, M. Thalhammer, S. Hickel (2020)
Journal of the Atmospheric Sciences 77: 3193-3210. doi: 10.1175/JAS-D-19-0342.1
We present direct numerical simulations of inertia–gravity waves breaking in the middle–upper mesosphere. We consider two different altitudes, which correspond to the Reynolds number of 28 647 and 114 591 based on wavelength and buoyancy period. While the former was studied by Remmler et al., it is here repeated at a higher resolution and serves as a baseline for comparison with the high-Reynolds-number case.
Influence of upstream disturbances on the primary and secondary instabilities in a supersonic separated flow over a backward-facing step
W. Hu, S. Hickel, B.W. van Oudheusden (2020)
Phys. Fluids 32: 056102. doi: 10.1063/5.0005431
Dynamics of unsteady asymmetric shock interactions
L. Laguarda, S. Hickel, F.F.J. Schrijer, B.W. van Oudheusden (2020)
Journal of Fluid Mechanics 888: A18. doi: 10.1017/jfm.2020.28
The response of asymmetric and planar shock interactions to a continuous excitation of the lower incident shock is investigated numerically. Incident shock waves and centred expansion fans are generated by two wedges asymmetrically deflecting the inviscid free stream flow at Mach 3.
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 Reb = 110 000.
Transitional Flow Dynamics Behind a Micro-Ramp
J. Casacuberta, K.J. Groot, Q. Ye, S. Hickel (2020)
Flow Turbulence and Combustion 104: 533-552. doi: 10.1007/s10494-019-00085-1
Micro-ramps are popular passive flow control devices which can delay flow separation by re-energising the lower portion of the boundary layer. We compute the laminar base flow, the instantaneous transitional flow, and the mean flow around a micro-ramp immersed in a quasi-incompressible boundary layer at supercritical roughness Reynolds number.
Rossby-number effects on columnar eddy formation and the energy dissipation law in homogeneous rotating turbulence
T. Pestana, S. Hickel (2020)
Journal of Fluid Mechanics 885: A7. doi: 10.1017/jfm.2019.976
Two aspects of homogeneous rotating turbulence are quantified through forced direct numerical simulations in an elongated domain, which, in the direction of rotation, is approximately 340 times larger than the typical initial eddy size. First, by following the time evolution of the integral length scale along the axis of rotation ℓ‖, the growth rate of the columnar eddies and its dependence on the Rossby number ??? is determined as ?=3.90exp(−16.72???) for 0.06⩽???⩽0.31, where ? is the non-dimensional growth rate. Second, a scaling law for the energy dissipation rate ?? is sought.