一様等方性を持つ強制乱流の渦構造

概要

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Three-dimensional forced homogeneous isotropic turbulence is investigated by a direct numerical simulation of the Navier-Stokes equations for an incompressible flow. Although homogeneous isotropic turbulence is an idealized model of turbulent phenomena, it is an excellent one for studying the energy cascade process and small scale turbulent structure. There are many experiments on turbulence, but it is difficult to collect spatial data from experiments. The recent development of supercomputers makes large scale direct simulations possible, and spatial structure of the turbulence can be examined through it. Thus we have developed aparallelized direct numerical simulation code for a forced homogeneous isotropic turbulence, Our objective is to investigate the structure of vorticity of the small scale turbulence, We employed the Fourier transform method with 2563 Fourier modes. The Taylor microscale Raynolds number, R\lambda, is about 110 at statistically steady state. In this calculation, the worm-shaped structures appear by observing the contour surface of vorticity field, and we fourld that worms are combined to form a sheet-shaped structure, and then the sheet rolls into a worm as time progresses.
九州大学の論文