Stretched-Vortex based Subgrid-scale Modeling of Variable-Density Flows

Sidharth, G. S.; Candler, Graham V.; Dimotakis, Paul E.

doi:10.2514/6.2015-2782

Cited by 2 publications

(1 citation statement)

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“…Modeling based on the transport of second-moments is more popular in RANS-based approach for variable-density flows and most proposed LES models for the subfilter-scale (SFS) or subgrid-scale (SGS) terms are based on firstorder closures [25]. These include the eddy-viscosity type SFS/SGS closure [26][27][28] and the stretched-vortex approach, such as [29,30]. There is still a lack of research on the application of second-moments for the closure of SFS/SGS terms in LES.…”

Section: Introductionmentioning

confidence: 99%

Analysis of second-moments and their budgets for Richtmyer-Meshkov instability and variable-density turbulence induced by re-shock

Wong¹,

Baltzer²,

Livescu³

et al. 2021

Preprint

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The nonlinear Richtmyer-Meshkov instability and mixing transition induced by a Mach 1.45 shock and subsequent re-shock at an interface between two ideal gases (sulphur hexafluoride and air) with high Atwood number are studied with second-moment analysis using data from highresolution compressible Navier-Stokes simulations. The analysis first addresses the importance of second-order moments: turbulent mass flux and density-specific-volume covariance, together with their transport equations. These quantities play an essential role on the development of Favreaveraged Reynolds stress and turbulent kinetic energy in this variable-density flow. Then, grid sensitivities and the time evolution of the second-moment quantities are investigated, followed by a detailed study of the transport equations of the second-moments using fully resolved data before re-shock. After re-shock, budgets of large-scale second-moments, which have insignificant influence from numerical regularization, are studied with the effects of subfilter-scale stress accounted. The effects of subfilter-scale stress on the budgets of large-scale second-moments with different levels of filtering are also examined.

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