1Theoretical Division and CNLS, MS B258, Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.A. 2CCIM, MS 0370, Sandia National Laboratories, Albuquerque, NM 87185, U.S.A.
Intermittency and Thermalization in Turbulence
ZHU Jian-Zhou1, Mark Taylor2
1Theoretical Division and CNLS, MS B258, Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.A. 2CCIM, MS 0370, Sandia National Laboratories, Albuquerque, NM 87185, U.S.A.
摘要A dissipation rate, which grows faster than any power of the wave number in Fourier space, may be scaled to lead a hydrodynamic system to actually or potentially converge to its Galerkin truncation. Actual convergence here means the asymptotic truncation at a finite wavenumber kG above which modes have no dynamics; and, we define potential convergence for the truncation at kG which, however, grows without bound. Both types of convergence can be obtained with the dissipation rate μ[cosh (κ/κ_c)-1]that behaves as k2 (newtonian) and exp{κ/κ_c}for small and large κ/κ_c respectively. Competing physics of cascade, thermalization and dissipation are discussed for numerical Navier-Stokes turbulence, emphasizing the intermittency growth issue.
Abstract：A dissipation rate, which grows faster than any power of the wave number in Fourier space, may be scaled to lead a hydrodynamic system to actually or potentially converge to its Galerkin truncation. Actual convergence here means the asymptotic truncation at a finite wavenumber kG above which modes have no dynamics; and, we define potential convergence for the truncation at kG which, however, grows without bound. Both types of convergence can be obtained with the dissipation rate μ[cosh (κ/κ_c)-1]that behaves as k2 (newtonian) and exp{κ/κ_c}for small and large κ/κ_c respectively. Competing physics of cascade, thermalization and dissipation are discussed for numerical Navier-Stokes turbulence, emphasizing the intermittency growth issue.
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2010, Vol. 27 
