Type: Article
Publication Date: 2009-12-31
Citations: 152
DOI: https://doi.org/10.2140/apde.2009.2.361
Let d ≥ 3. We consider the global Cauchy problem for the generalized Navier-Stokes systemfor u : ޒ + × ޒ d → ޒ d and p : ޒ + × ޒ d → ,ޒ where u 0 : ޒ d → ޒ d is smooth and divergence free, and D is a Fourier multiplier whose symbol m : ޒ d → ޒ + is nonnegative; the case m(ξ ) = |ξ | is essentially Navier-Stokes.It is folklore that one has global regularity in the critical and subcritical hyperdissipation regimes m(ξ ) = |ξ | α for α ≥ (d + 2)/4.We improve this slightly by establishing global regularity under the slightly weaker condition that m(ξ ) ≥ |ξ | (d+2)/4 /g(|ξ |) for all sufficiently large ξ and some nondecreasing function g : ޒ + → ޒ + such that ∞ 1 ds/(sg(s) 4 ) = +∞.In particular, the results apply for the logarithmically supercritical dissipation m(ξ ) := |ξ | (d+2)/4 / log(2 + |ξ | 2 ) 1/4 .