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Intermittency and Anomalous scaling in turbulence - Victor S. L'vov ...

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• Exact “Dissipative-bridge” relationships, (L’vov-Procaccia-96)<br />

NSE:<br />

∂v<br />

+ (v · ∇)v + ∇p = ν ∆v<br />

∂t<br />

⇒<br />

∂v<br />

∂t + P <br />

(v · ∇)v <br />

= ν ∆v<br />

P: transversal projector, Wr: r-separated velocity <strong>in</strong>crement.<br />

NSE for Wr schematically :<br />

Wr ∂Wr<br />

∂t + Wr P <br />

<br />

(Wr · ∇)Wr<br />

∂Wr<br />

∂t + P <br />

<br />

(Wr · ∇)Wr<br />

= ν ∆Wr ⇒<br />

= Wrν ∆Wr ⇒ −ν(∇Wr) ·(∇Wr) −ε(r) .<br />

Thus, <strong>in</strong>side of the average operator, 〈. . .〉, the viscous range object ε(r)<br />

can be evaluated as the <strong>in</strong>ertial range object Wr P <br />

<br />

(Wr · ∇)Wr<br />

ε(r) ⇒ W3 r<br />

r<br />

W 3 r /r:<br />

⇒ µn = n − ζ3n ⇒ µ2 = 2 − ζ6 0.3 ÷ 0.4<br />

Exact “dissipative-bridge” relations µn = n − ζ3n<br />

are known <strong>in</strong> liter-<br />

ature as a consequence of Kolmogorov “Ref<strong>in</strong>ed Similarity” hypothesis.<br />

5

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