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dc.contributor.authorYoungs, D. L.
dc.contributor.authorThornber, B. J. R.
dc.date.accessioned2020-06-12
dc.date.available2020-06-12
dc.date.issued2020-06-12
dc.identifier.urihttps://hdl.handle.net/2123/22484
dc.descriptionThis is a technical report detailing in full the development of a novel Buoyancy Drag model which can accurately represent the growth of a turbulent layer from transitional through to self-similar. It also provides insight into the underlying physics of the mixing layer itself.en_AU
dc.description.abstractThe Buoyancy-Drag model is a simple model, based on ordinary differential equations, for estimating the growth in the width of a turbulent mixing zone at an interface between fluids of different density due to Richtmyer-Meshkov and Rayleigh-Taylor instabilities. The model is calibrated to give the required self-similar behaviour for mixing in simple situations. However, the early stages of the mixing process are very dependent on the initial conditions and modifications to the Buoyancy-Drag model are then needed to obtain correct results. In a recent paper, Thornber et al. [Phys. Fluids. 29 (2017) 105107], a range of three-dimensional simulation techniques were used to calculate the evolution of the mixing zone integral width due to single-shock Richtmyer-Meshkov mixing from narrowband initial random perturbations. Further analysis of the results of these simulations gives greater insight into the transition from the initial linear behaviour to late-time self-similar mixing and provides a way of modifying the Buoyancy-Drag model to treat the initial conditions accurately. Higher resolution simulations are used to calculate the early time behaviour more accurately and compare with a multi-mode model based on the impulsive linear theory. The analysis of the iLES data also gives a new method for estimating the growth exponent ,q ,(mixing zone width ~ t^q). The estimates of q are consistent with the theoretical model of Elbaz & Shvarts [Physics of Plasmas (2018), 25, 062126].en_AU
dc.language.isoenen_AU
dc.subjectTurbulence, Richtmyer-Meshkov, Buoyancy Drag, mixing, compressible, shock, computational fluid dynamicsen_AU
dc.titleEarly Time Modifications to the Buoyancy-Drag Model for Richtmyer-Meshkov mixingen_AU
dc.typeReport, Technicalen_AU
dc.subject.asrc091508en_AU
dc.subject.asrc091501en_AU
dc.identifier.doi10.25910/5f1610af74f6a
dc.type.pubtypePre-printen_AU


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