Localized dynamic kinetic-energy model for compressible wavelet-based adaptive large-eddy simulation

Stefano, Giuliano De; Dymkoski, Eric; Vasilyev, Oleg V.

doi:10.1103/physrevfluids.7.054604

Cited by 6 publications

(3 citation statements)

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“…As to future perspectives, the possibility of applying more sophisticated models based on wavelet multiscale methods [45,46] is under study. Very recently, this innovative approach employing the adaptive wavelet collocation method to solve the energetic flow structures on dynamic grids has been further developed for supersonic flows [47][48][49], and novel wavelet-based adaptive URANS models [50,51] might be explored in the present context [28].…”

Section: Discussionmentioning

confidence: 99%

Hybrid VOF–Lagrangian CFD Modeling of Droplet Aerobreakup

Rossano

Stefano

2022

Applied Sciences

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A hybrid VOF–Lagrangian method for simulating the aerodynamic breakup of liquid droplets induced by a traveling shock wave is proposed and tested. The droplet deformation and fragmentation, together with the subsequent mist development, are predicted by using a fully three-dimensional computational fluid dynamics model following the unsteady Reynolds-averaged Navier–Stokes approach. The main characteristics of the aerobreakup process under the shear-induced entrainment regime are effectively reproduced by employing the scale-adaptive simulation method for unsteady turbulent flows. The hybrid two-phase method combines the volume-of-fluid technique for tracking the transient gas–liquid interface on the finite volume grid and the discrete phase model for following the dynamics of the smallest liquid fragments. The proposed computational approach for fluids engineering applications is demonstrated by making a comparison with reference experiments and high-fidelity numerical simulations, achieving acceptably accurate results without being computationally expensive.

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Section: Discussionmentioning

confidence: 99%

Hybrid VOF–Lagrangian CFD Modeling of Droplet Aerobreakup

Rossano

Stefano

2022

Applied Sciences

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“…In the current a priori modelling framework, the true LES field is not available and should be estimated. One possible approach is to use a threshold filtering (Goldstein & Vasilyev 2004;De Stefano & Vasilyev 2012;De Stefano, Dymkoski & Vasilyev 2022), which is not followed by the current study. In the Fourier context, the resolved-scale motions can be estimated using scale-sharp filtering.…”

Section: Wmra Framework For Sgs Modellingmentioning

confidence: 99%

“…In evaluating the triadic interaction terms in (2.5), the scale decomposition proposed by Meneveau (1991) is used, by which velocity field is decomposed into components smaller and larger than a prescribed filter cutoff scale via Using (2.6), the nonlinear convection term is rewritten as In the current a priori modelling framework, the true LES field is not available and should be estimated. One possible approach is to use a threshold filtering (Goldstein & Vasilyev 2004; De Stefano & Vasilyev 2012; De Stefano, Dymkoski & Vasilyev 2022), which is not followed by the current study. In the Fourier context, the resolved-scale motions can be estimated using scale-sharp filtering.…”

Section: Wmra Framework For Sgs Modellingmentioning

confidence: 99%

Optimising subgrid-scale closures for spectral energy transfer in turbulent flows

Nabavi,

Kim

2024

J. Fluid Mech.

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Subgrid-scale (SGS) modelling is formulated using a local transport of spectral kinetic energy estimated by a wavelet multiresolution analysis. Using a spectrally and spatially local decomposition by wavelet, the unresolved inter-scale energy transfer and modelled SGS dissipation are evaluated to enforce explicitly and optimally their balance a priori over a range of large-eddy simulation (LES) filter widths. The formulation determines SGS model constants that optimally describe the spectral energy balance between the resolved and unresolved scales at a given cutoff scale. The formulation is tested for incompressible homogeneous isotropic turbulence (HIT). One-parameter Smagorinsky- and Vreman-type eddy-viscosity closures are optimised for their model constants. The algorithm discovers the theoretical prediction of Lilly (The representation of small-scale turbulence in numerical simulation experiments. In Proceedings of the IBM Scientific Computing Symposium on Environmental Sciences, pp. 195–210) at a filter cutoff scale in the inertial subrange, whereas the discovered constants deviate from the theoretical value at other cutoff scales so that the spectral optimum is achieved. The dynamic Smagorinsky model used a posteriori shows a suboptimal behaviour at filter scales larger than those in the inertial subrange. A two-parameter Clark-type closure model is optimised. The optimised constants provide evidence that the nonlinear gradient model of Clark et al. (J. Fluid Mech., vol. 91, issue 1, 1979, pp. 1–16) is prone to numerical instability due to its model form, and combining the pure gradient model with a dissipative model such as the classic Smagorinsky model enhances numerical stability but the standard mixed model is not optimal in terms of spectral energy transfer. A posteriori analysis shows that the optimised SGS models produce accurate LES results.

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