Network structure of two-dimensional decaying isotropic turbulence

Decaying Two-dimensional Turbulence in Bounded Flows

Two-dimensional turbulence in unbounded or double periodic domains, in Navier-Stokes fluids and plasmas has been investigated intensively during the last decades by means of numerical simulations. The presence of an inertial range in the energy spectrum of these flows has been well documented. As two-dimensional flows exhibit an inverse cascade in the energy, coherent structures comparable with...

Velocity autocorrelations of decaying isotropic homogeneous turbulence

Velocity autocorrelations and the mean-square displacements of fluid particles are obtained for decaying, isotropic homogeneous turbulence by numerical simulation of the flow field, using 1283 and 256’ grids, and tracking several tens of thousands of fluid particles, using a third-order interpolation scheme. A self-preserving Lagrangian velocity autocorrelation coefficient is found in terms of ...

An ‘ideal’ form of decaying two-dimensional turbulence

A coalescence model for freely decaying two-dimensional turbulence

– We propose a ballistic coalescence model (punctuated-Hamiltonian approach) mimicking the fusion of vortices in freely decaying two-dimensional turbulence. A temporal scaling behaviour is reached where the vortex density evolves like t. A mean-field analytical argument yielding the approximation ξ = 4/5 is shown to slightly overestimate the decay exponent ξ whereas Molecular Dynamics simulatio...

Regional statistics in confined two-dimensional decaying turbulence.

Two-dimensional decaying turbulence in a square container has been simulated using the lattice Boltzmann method. The probability density function (PDF) of the vorticity and the particle distribution functions have been determined at various regions of the domain. It is shown that, after the initial stage of decay, the regional area averaged enstrophy fluctuates strongly around a mean value in t...