Publication Date:
2018-10-27
Description:
In statistically stationary conditions, the turbulent energy spectrum in a high Reynolds number flow exhibits a k −5/3 (Kolmogorov) regime, with a faster decay at larger, dissipative wavenumbers. Here, we investigate how the energy spectrum of a turbulent flow evolves in time when turbulence decays freely, in the absence of forcing. Results from direct numerical simulation of decaying turbulence in a periodic box with several different initial conditions suggest a generalized self-similar spectrum, depending on ##IMG## [http://ej.iop.org/images/1367-2630/20/10/103035/njpaae72dieqn1.gif] {${k}_{s}=k\times \eta (t)$} and ##IMG## [http://ej.iop.org/images/1367-2630/20/10/103035/njpaae72dieqn2.gif] {${k}_{l}=k\times L(t)$} , where η ( t ) and L ( t ) are, respectively, the small (Kolmogorov) and large scales of the flow. A closure method allows us to obtain an explicit form of the spectrum, which repr...
Electronic ISSN:
1367-2630
Topics:
Physics
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