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7. Turbulence is not one of the great unsolved problems in physics. Physics tells us exactly how turbulence emerges as a direct consequence of local mass and momentum conservation. We can create multiparticle computer models such as lattice gas automata that generate turbulence at large length and time scales.
Sep 26, 2022 · 1. a newbie in turbulence study, very confused about the concept of eddy, I feel the word "eddy" having two meanings in fluid-mechanics maybe more and i'm not sure if i understand correctly. we can say, in a flow, there is a large or small eddy in this region, in this meaning, eddy means rotating fluid material, we can say an eddy in this place ...
Nov 1, 2019 · Fluid turbulence is a highly complex and non-linear chaotic phenomenon. Great difficulties and complications are encountered when trying to accurately and robustly calculate or simulate fluid flows, due to the chaotic, multi-scale effects of turbulence.
Spalding [Launder and Spalding (1972)] and Wilcox and Alber (1972) identify ωt ω t as the RMS fluctuating vorticity, which is also known as enstrophy. So in essence, enstrophy is believed to be directly related to the energy cascade of turbulence. "Believed" is the key word there, as there are several different interpretations of ωt ω t.
Nevertheless, there is still no downward cascade for the special case of 2d fluid turbulence. The reason there is that there is a second continuous integral conserved quantity in this special case, the enstropy, which is the square of the curl of the 2d velocity. S = ∫(∂yVx −∂xVy)2dxdy S = ∫ (∂ y V x − ∂ x V y) 2 d x d y.
Sep 15, 2018 · The delicate balance of turbulent kinetic energy in that cascade, however, is described at all scales by the unsteady 3-D Navier-Stokes equations: turbulent flow still has to satisfy continuity and balance of momentum... [I]f we have a consistent discretisation and make the mesh fine enough, discretisation errors will become negligible.
The statement that "fluids are fractal" is not quite correct (or at the very least is not precise). Instead what really happens is that energy in fluids transitions to higher and higher frequencies via a recursive formula which looks slightly fractal-like (called the "Selection rule"). This is one of the most famous results in fluid mechanics ...
Aug 30, 2022 · Turbulence is the time-dependent chaotic behaviour seen in many fluid flows. It is generally believed that it is due to the inertia of the fluid as a whole: the culmination of time-dependent and convective acceleration ;
Apr 1, 2020 · It explains some passages that leads to the dependency f−5/3 f − 5 / 3 (page 73), and the demonstration it is not the same. The paper of Kolmogorv does not outlines only the hypotheses but introduce the so called 2/3 law that leads to the -5/3 law (I am missing this passage) – Ashish Bhigah. Apr 1, 2020 at 21:00.
