<p>We establish universal scaling laws and quantify aging in three-dimensional uniformly heated hard sphere granular gases through large-scale event-driven molecular dynamics (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(N=500{,}000\)</EquationSource> </InlineEquation>). We report three primary quantitative results: (i) The characteristic energy decay time exhibits a universal inverse scaling <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\tau _0 \propto \epsilon ^{-1.03 \pm 0.02}\)</EquationSource> </InlineEquation> with the dissipation parameter <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\epsilon = 1 - e^2\)</EquationSource> </InlineEquation>. (ii) The steady-state temperature follows a precise power-law <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(T_{\textrm{steady}} \propto \epsilon ^{-1.51 \pm 0.03}\)</EquationSource> </InlineEquation>, reflecting the non-linear balance between thermostat heating and collisional dissipation. (iii) The velocity autocorrelation function <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\bar{A}(\tau _w, \tau )\)</EquationSource> </InlineEquation> demonstrates pronounced aging, with decay rates <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\lambda \)</EquationSource> </InlineEquation> following a power-law slowing down <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\lambda (\tau _w) \propto \tau _w^{-0.82 \pm 0.05}\)</EquationSource> </InlineEquation>. (iv) A characteristic cluster size <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\xi (\tau _w)\)</EquationSource> </InlineEquation> extracted from <i>g</i>(<i>r</i>) grows as <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\xi \propto \tau _w^{0.38\pm 0.04}\)</EquationSource> </InlineEquation>, and the VACF decay rate follows <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\lambda \propto \xi ^{-2.16\pm 0.20}\)</EquationSource> </InlineEquation>, providing the first quantitative structural-dynamical link between spatial coarsening and velocity decorrelation in a 3D driven granular gas. The aging exponent <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(\lambda (\tau _w) \propto \tau _w^{-0.82\pm 0.05}\)</EquationSource> </InlineEquation>, verified over 1.6 decades of <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(\tau _w\)</EquationSource> </InlineEquation> and robust across two noise intensities and two densities, provides the first quantitative evidence for aging dynamics in the driven steady-state regime, distinct from previously studied freely cooling cases.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Universal aging dynamics and scaling laws in three-dimensional driven granular gases

  • Rameez Farooq Shah,
  • Syed Rashid Ahmad

摘要

We establish universal scaling laws and quantify aging in three-dimensional uniformly heated hard sphere granular gases through large-scale event-driven molecular dynamics ( \(N=500{,}000\) ). We report three primary quantitative results: (i) The characteristic energy decay time exhibits a universal inverse scaling \(\tau _0 \propto \epsilon ^{-1.03 \pm 0.02}\) with the dissipation parameter \(\epsilon = 1 - e^2\) . (ii) The steady-state temperature follows a precise power-law \(T_{\textrm{steady}} \propto \epsilon ^{-1.51 \pm 0.03}\) , reflecting the non-linear balance between thermostat heating and collisional dissipation. (iii) The velocity autocorrelation function \(\bar{A}(\tau _w, \tau )\) demonstrates pronounced aging, with decay rates \(\lambda \) following a power-law slowing down \(\lambda (\tau _w) \propto \tau _w^{-0.82 \pm 0.05}\) . (iv) A characteristic cluster size \(\xi (\tau _w)\) extracted from g(r) grows as \(\xi \propto \tau _w^{0.38\pm 0.04}\) , and the VACF decay rate follows \(\lambda \propto \xi ^{-2.16\pm 0.20}\) , providing the first quantitative structural-dynamical link between spatial coarsening and velocity decorrelation in a 3D driven granular gas. The aging exponent \(\lambda (\tau _w) \propto \tau _w^{-0.82\pm 0.05}\) , verified over 1.6 decades of \(\tau _w\) and robust across two noise intensities and two densities, provides the first quantitative evidence for aging dynamics in the driven steady-state regime, distinct from previously studied freely cooling cases.