On Energy Cascades in General Flows: A Lagrangian Application

AbstractA series of high-energy, up to 20 keV, displacement cascades in iron have been investigated for times up to 200 ps at 100 K using the method of molecular dynamics simulation. Thesimulations were carried out using the MOLDY code and a modified version of the many-bodyinteratomic potential developed by Finnis and Sinclair. The paper focuses on those results obtained at the highest energies, 10 and 20 keV. The results indicate that the fraction of the Frenkel pairs surviving in-cascade recombination remains fairly high in iron and that the fraction of the surviving point defects that cluster is lower than in materials such as copper. In particular, vacancy clustering appears to be inhibited in iron. Some of the interstitial clusters were observed to exhibit an unexpectedly complex, three-dimensional morphology. The observations are discussed in terms of their relevance to microstructural evolution and mechanical property changes in irradiated iron-based alloys.

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Multi-scale modeling of self-irradiation effects in plutonium alloys - Molecular dynamic simulations results

MRS Proceedings ◽

10.1557/proc-0893-jj05-04 ◽

2005 ◽

Vol 893 ◽

Cited By ~ 2

Author(s):

Lilian Berlu ◽

Gaelle Rosa ◽

Philippe Faure ◽

Nathalie Baclet ◽

Gérald Jomard

Keyword(s):

Point Defects ◽

Metal Structure ◽

Irradiation Effects ◽

Dynamic Simulations ◽

Α Decay ◽

Multi Scale ◽

Scale Modeling ◽

Energy Cascades ◽

First Results ◽

Multi Scale Modeling

AbstractThe plutonium α decay leads to the formation of numerous point defects in the metal structure. The multi-scale modeling of self-irradiation effects in plutonium alloys needs a quantitative knowledge of defects population properties. In this work, we initiated a parametric study of molecular dynamics displacement cascade simulations to get properties of defects microstructure such as number of point defects, number and size of clusters, spatial repartition and spatial expansion of the cascade. These data constitute some of the input parameters for the mesoscopic scale simulations. First results obtained for two 2 keV energy cascades simulations are presented and discussed.

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Image Intensifier Photography of Ultrahigh Energy Cascades in an Ionization Spectrometer. I. Apparatus

Review of Scientific Instruments ◽

10.1063/1.1684685 ◽

1970 ◽

Vol 41 (7) ◽

pp. 1007-1012 ◽

Cited By ~ 1

Author(s):

R. W. Huggett ◽

T. Sandor ◽

J. E. Webb

Keyword(s):

Image Intensifier ◽

Ultrahigh Energy ◽

Energy Cascades

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Simulating high energy cascades in metals

Radiation Effects and Defects in Solids ◽

10.1080/10420159408219803 ◽

1994 ◽

Vol null (1) ◽

pp. 453-460

Author(s):

H. L. Heinisch

Keyword(s):

High Energy ◽

Energy Cascades

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Inverse energy cascades in three‐dimensional turbulence

Physics of Fluids B Plasma Physics ◽

10.1063/1.859900 ◽

1991 ◽

Vol 3 (3) ◽

pp. 511-514 ◽

Cited By ~ 17

Author(s):

Murshed Hossain

Keyword(s):

Three Dimensional ◽

Energy Cascades

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Non-universal scaling transition of momentum cascade in wall turbulence

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.309 ◽

2019 ◽

Vol 871 ◽

Cited By ~ 3

Author(s):

Xi Chen ◽

Fazle Hussain ◽

Zhen-Su She

Keyword(s):

Wall Turbulence ◽

Normal Velocity ◽

Large Set ◽

Flow State ◽

Energy Cascades ◽

Full Coupling ◽

Turbulent Momentum ◽

Analytic Prediction ◽

Prevailing View ◽

Near Wall

As a counterpart of energy cascade, turbulent momentum cascade (TMC) in the wall-normal direction is important for understanding wall turbulence. Here, we report an analytic prediction of non-universal Reynolds number ($Re_{\unicode[STIX]{x1D70F}}$) scaling transition of the maximum TMC located at $y_{p}$. We show that in viscous units,$y_{p}^{+}$(and$1+\overline{u^{\prime }v^{\prime }}_{p}^{+}$) displays a scaling transition from$Re_{\unicode[STIX]{x1D70F}}^{3/7}$($Re_{\unicode[STIX]{x1D70F}}^{-6/7}$) to$Re_{\unicode[STIX]{x1D70F}}^{3/5}$($Re_{\unicode[STIX]{x1D70F}}^{-3/5}$) in turbulent boundary layer, in sharp contrast to that from$Re_{\unicode[STIX]{x1D70F}}^{1/3}$($Re_{\unicode[STIX]{x1D70F}}^{-2/3}$) to$Re_{\unicode[STIX]{x1D70F}}^{1/2}$($Re_{\unicode[STIX]{x1D70F}}^{-1/2}$) in a channel/pipe, countering the prevailing view of a single universal near-wall scaling. This scaling transition reflects different near-wall motions in the buffer layer for small$Re_{\unicode[STIX]{x1D70F}}$and log layer for large $Re_{\unicode[STIX]{x1D70F}}$, with the non-universality being ascribed to the presence/absence of mean wall-normal velocity $V$. Our predictions are validated by a large set of data, and a probable flow state with a full coupling between momentum and energy cascades beyond a critical$Re_{\unicode[STIX]{x1D70F}}$is envisaged.

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