Direct Numerical Simulation of Isothermal Wake: DNS Noise, Strong Anisotropy Turbulence, and Vortex Dislocation Generation Mechanism

Autor:	Katsuhisa Noto
Rok vydání:	2009
Předmět:	Physics Numerical Analysis Turbulence Direct numerical simulation Reynolds number Laminar flow Mechanics Wake Condensed Matter Physics Computer Science Applications Vortex Physics::Fluid Dynamics symbols.namesake Mechanics of Materials Modeling and Simulation Vertical direction symbols Cylinder
Zdroj:	Numerical Heat Transfer, Part B: Fundamentals. 56:167-189
ISSN:	1521-0626 1040-7790
DOI:	10.1080/10407790903116402
Popis:	The isothermal wake from a circular cylinder at Reynolds number Re = 300 is analyzed numerically by direct numerical simulation (DNS). The DNS noise, anisotropic turbulence, and vortex dislocation mechanism are elucidated as follows: The coordinates x, y, and z are the vertical direction, horizontal direction perpendicular to the cylinder axis, and direction along the cylinder axis, and the velocities u, v, and w are in the x, y, and z directions. The DNS noise in velocity w along the cylinder axis arising in the DNS at Re = 100 was obtained by computation. The DNS noise was verified to have an amplitude of 1 × 10−8 times the amplitudes of the vertical velocity u and the horizontal velocity v, to be neither turbulent nor laminar, and to be the disorderly accumulated result of round-off errors. The streaklines were obtained by DNS at Re = 300, the strong anisotropy in turbulence was determined by power spectrum density (PSD) and, employing these, the mechanism in the wake behavior is discussed. The degree ...
Databáze:	OpenAIRE
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