Velocity-Gradient Dynamics in Turbulence: Effect of Viscosity and Forcing
作者： Eunhwan Jeong , Sharath S. Girimaji
DOI: 10.1007/S00162-002-0084-7
关键词: Singularity 、 Turbulence 、 Velocity gradient 、 Mechanics 、 Strain rate tensor 、 K-epsilon turbulence model 、 Euler equations 、 Classical mechanics 、 Mathematics 、 Vorticity 、 Euler's formula
摘要: The restricted Euler equation is a promising but incomplete model for velocity-gradient dynamics in turbulent flows. While it captures many of the geometric features vorticity vector and strain rate tensor, viscous anisotropic pressure Hessian effects are not accounted satisfactorily. Inadequate viscous-effect modeling causes velocity gradients to diverge finite time, rendering unsuitable practical applications. We perform Lagrangian frame analysis comprehend fully physics relaxation time scale propose variable time-scale that can adequately account deformation history. Most importantly, finite-time singularity (divergence gradients) problem resolved with present model. also forcing used numerical simulations sustain stationary isotropic turbulence. Detailed comparison new DNS data reveals good agreement.
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