Scale-Resolving Simulations with a Low-Dissipation Low-Dispersion Second-Order Scheme for Unstructured Flow Solvers

Probst, Axel; Löwe, Johannes; Reuß, Silvia; Knopp, Tobias; Kessler, Roland

doi:10.2514/1.j054957

Cited by 38 publications

(22 citation statements)

References 37 publications

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“…Moreover, the central flux terms employ an additional gradient extrapolation that effectively increases the discretization stencil and is used to reduce the dispersion error of the scheme. Both ingredients are essential for accurate WMLES results with the unstructured TAU code ( Probst et al, 2016a ). Note that in the present zonal RANS-WMLES computations, the LD2 scheme is only active in the respective WM-LES region downstream of the interface.…”

Section: Flow Solversmentioning

confidence: 99%

Evaluation of grey area mitigation tools within zonal and non-zonal RANS-LES approaches in flows with pressure induced separation

Probst¹,

Schwamborn²,

Garbaruk

et al. 2017

International Journal of Heat and Fluid Flow

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Hybrid RANS-LES computations of the separated flow over a wall-mounted hump are presented, which employ different grey-area mitigation techniques in the framework of a structured and an unstructured flow solver. Two zonal approaches using different synthetic-turbulence generators at the RANS-LES interface, as well as a non-zonal approach based on a shear-layer-adapted subgrid scale are compared in detail with validation data from a wind-tunnel experiment. Irrespective of the applied flow solver, the different methods are shown to be similarly effective in reducing the grey area compared to the basic hybrid RANS-LES model, and thus provide satisfying mean-flow predictions of the pressure-induced separation.

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Section: Flow Solversmentioning

confidence: 99%

Evaluation of grey area mitigation tools within zonal and non-zonal RANS-LES approaches in flows with pressure induced separation

Probst¹,

Schwamborn²,

Garbaruk

et al. 2017

International Journal of Heat and Fluid Flow

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“…4.2.1. To allow improved accuracy in resolved regions and improved stability in non-resolved (RANS) regions, a hybrid low dissipation low dispersion central scheme is applied that has been extensively tested and validated for hybrid RANS-LES [14]. The skew-symmetric central scheme used for the convective fluxes [9] for one calorically perfect gas was recently extended for multiple species.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the low dissipative nature of the numerical scheme, a fourth-order artificial matrix dissipation term is added for improved stability [14] which was optimized in LES of channel flows [15]. The artificial dissipation is preconditioned to obtain optimally tuned accuracy also in low Mach number regions [23].…”

Section: Methodsmentioning

confidence: 99%

Sensitivity of scale resolving aft-body flow simulations to numerical model parameter variations

Schumann

Hannemann

2021

CEAS Space J

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The sensitivity of hybrid RANS-LES methods like Improved Delayed Detached Eddy Simulation (IDDES) to numerical model parameter variations related to generic space launch vehicle aft-body flows is investigated. In particular, the changes resulting from the choice of the time-step size, the turbulence model, the fluid modelling, the circumferential grid resolution, the filter length definition, and the data collection period is considered. The results are also compared to experimental and numerical data taken from the available literature. The sensitivity to the time-step size and the turbulence model is minuscule with respect to the obtained mean flow field, wall pressure distributions, azimuthal modes, and wall pressure frequency spectra. However, circumferential resolution, fluid model, and filter length definition affect the solution to a higher extent. Buffeting spectra are very sensitive to the data collection period.

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“…A local switch to 1st order scheme by according artificial dissipation is used to stabilize the simulations at shocks locations. The central flux terms employ an additional gradient extrapolation that increases the discretization stencil and is used to reduce the dispersion error of the scheme [19].…”

Section: Numerical Approachmentioning

confidence: 99%

Investigation of transonic aerodynamics on a triple-delta wing in side slip conditions

2022

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The vortex-dominated flow around the triple-delta wing ADS-NA2-W1 aircraft is investigated in order to achieve a better understanding of the flow physics phenomena that occur over the aircraft particularly at the transonic speed condition. Both URANS and scale-resolving DDES have been employed in order to explore the range of suitability of current CFD methods. The Spalart–Allmaras One-Equation Model with corrections for negative turbulent viscosity and Rotation/Curvature (SA-negRC) is employed to close the RANS equations, whereas the SAneg-based DDES model is applied in the scale-resolving computations. The DLR TAU-Code is used to perform the numerical simulations. The deficiencies of the URANS results are illustrated and promising improvements are reached employing the SAneg-DDES numerical method. The hybrid method results show great advancement in the prediction of the multiple-delta wing flow by revealing physical aspects which have not been seen from URANS with sufficient accuracy like vortex–vortex interaction and shock-vortex interaction. These phenomena furthermore explain in a clear way the improved prediction of the surface pressure coefficient over the aircraft and consequently of the aerodynamic force and moment coefficients.

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Scale-Resolving Simulations with a Low-Dissipation Low-Dispersion Second-Order Scheme for Unstructured Flow Solvers

Cited by 38 publications

References 37 publications

Evaluation of grey area mitigation tools within zonal and non-zonal RANS-LES approaches in flows with pressure induced separation

Evaluation of grey area mitigation tools within zonal and non-zonal RANS-LES approaches in flows with pressure induced separation

Sensitivity of scale resolving aft-body flow simulations to numerical model parameter variations

Investigation of transonic aerodynamics on a triple-delta wing in side slip conditions

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