On the Decay of Isotropic Turbulence
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We investigate the decay of freely-evolving, isotropic turbulence whose spectrum takes the form E(k→0)∼Ik4, I being Loitsyansky's integral. We report numerical simulations in a periodic domain whose dimensions, lbox, are much larger than the integral scale of the turbulence, l. We find that, provided lbox≫l and Re≫1, the turbulence evolves to a state in which Loitsyansky's integral is approximately constant and Kolmogorov's decay law, u2∼t−10/7, holds true. The approximate conservation of I in fully-developed turbulence implies that the long-range interactions between remote eddies, as measured by the triple correlations, are very weak.
KeywordsDirect Numerical Simulation Integral Scale Isotropic Turbulence Traditional Theory Periodic Domain
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