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Linearly Forced Isotropic TurbulenceStationary isotropic turbulence is often studied numerically by adding a forcing term to the Navier-Stokes equation. This is usually done for the purpose of achieving higher Reynolds number and longer statistics than is possible for isotropic decaying turbulence. It is generally accepted that forcing the Navier-Stokes equation at low wave number does not influence the small scale statistics of the flow provided that there is wide separation between the largest and smallest scales. It will be shown, however, that the spectral width of the forcing has a noticeable effect on inertial range statistics. A case will be made here for using a broader form of forcing in order to compare computed isotropic stationary turbulence with (decaying) grid turbulence. It is shown that using a forcing function which is directly proportional to the velocity has physical meaning and gives results which are closer to both homogeneous and non-homogeneous turbulence. Section 1 presents a four part series of motivations for linear forcing. Section 2 puts linear forcing to a numerical test with a pseudospectral computation.
Document ID
20040031711
Acquisition Source
Headquarters
Document Type
Other
Authors
Lundgren, T. S.
(Minnesota Univ. MN, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Center for Turbulence Research Annual Research Briefs 2003
Subject Category
Fluid Mechanics And Thermodynamics
Funding Number(s)
CONTRACT_GRANT: NCC2-1371
Distribution Limits
Public
Copyright
Public Use Permitted.
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