Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session L38: Turbulence Theory I
4:05 PM–6:41 PM,
Monday, November 19, 2018
Georgia World Congress Center Room: Ballroom 1/2
Chair: Michael Wilczek, Max Planck Institute
Abstract ID: BAPS.2018.DFD.L38.8
Abstract: L38.00008 : The large scale structure of decaying stratified Saffman turbulence*
5:36 PM–5:49 PM
(Aichi Inst. Tech.)
(Aichi Inst. Tech.)
We consider freely decaying turbulence of incompressible fluid evolving in the presence of imposed stratification in which the energy spectrum E(k) ~ k^2 at small wavenumber k. Turbulence with this kind of spectrum is called here Saffman turbulence. The turbulence field can be represented in terms of three eigenmodes of a linear operator including the buoyancy effect, say zeta_1 (voritical mode), zeta_2 and zeta_3 (wave modes). Within the linearized approximation ignoring the nonlinear coupling between the modes, the velocity correlation spectrum <|u_i(p)|^2> (no summation over i) in general oscillates in time due to the presence of buoyancy force, while the spectra Z_a(p)=<|zeta_a(p)|^2> (a=1,2,3) do not oscillate, where p is the wave vector. A simple analysis under certain assumptions shows that there are an infinite number of invariants associated with each of the spectra Z_1, Z_2 and Z_3 at small |p|. The invariants may depend on the direction of the wave vector p. Theoretical conjectures based on the analysis are examined by comparison with direct numerical simulation data.
*This study is partially supported by JSPS KAKENHI, grant # (S)16H06339.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DFD.L38.8
The American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics.
1 Physics Ellipse, College Park, MD 20740-3844
Editorial Office 1 Research Road, Ridge, NY 11961-2701 (631) 591-4000
Office of Public Affairs 529 14th St NW, Suite 1050, Washington, D.C. 20045-2001 (202) 662-8700