An ‘ideal’ form of decaying two-dimensional turbulence
Iwayama, T., Shepherd, T. G. and Watanabe, T. (2002) An ‘ideal’ form of decaying two-dimensional turbulence. Journal of Fluid Mechanics, 456. ISSN 0022-1120
To link to this article DOI: 10.1017/S0022112001007509
In decaying two-dimensional Navier-Stokes turbulence, Batchelor's similarity hypothesis fails due to the existence of coherent vortices. However, it is shown that decaying two-dimensional turbulence governed by the Harney-Hasegawa-Mima (CHM) equation ∂/∂t (V^2 φ-λ^2 φ)+J(φ,∇^2 φ)=D where D is a damping, is described well by Batchelor's similarity hypothesis for wave numbers k ≪ λ (the so-called AM regime). It is argued that CHM turbulence in the AM regime is a more `ideal' form of two-dimensional turbulence than is Navier-Stokes turbulence itself.