Eddy diffusivities in scalar transport
arXiv:cond-mat/9412115 · doi:10.1063/1.868651
Abstract
Standard and anomalous transport in incompressible flow is investigated using multiscale techniques. Eddy-diffusivities emerge from the multiscale analysis through the solution of an auxiliary equation. From the latter it is derived an upper bound to eddy-diffusivities, valid for both static and time-dependent flow. The auxiliary problem is solved by a perturbative expansion in powers of the Péclet number resummed by Padé approximants and by a conjugate gradient method. The results are compared to numerical simulations of tracers dispersion for three flows having different properties of Lagrangian chaos. It is shown on a concrete example how the presence of anomalous diffusion can be revealed from the singular behaviour of the eddy-diffusivity at very small molecular diffusivities.
21 Pages + 6 Figures Postscript (appended as .tar file), Latex submitted Phys of Fluids
Cited by in corpus (36)
- Dispersion of passive tracers in closed basins: beyond the diffusion coefficient
- On the strong anomalous diffusion
- Dust settling in local simulations of turbulent protoplanetary disks
- Renormalization group and anomalous scaling in a simple model of passive scalar advection in compressible flow
- Equilibrium and dynamical properties of two dimensional self-gravitating systems
- Coarse graining of master equations with fast and slow states
- Scalar transport in compressible flow
- A perturbative path integral study of active and passive tracer diffusion in fluctuating fields
- Magnetic field generation by pointwise zero-helicity three-dimensional steady flow of incompressible electrically conducting fluid
- Multiple-scale analysis and renormalization for pre-asymptotic scalar transport
- Chaotic mixing and transport in a meandering jet flow
- Langevin approach to generate synthetic turbulence
- Anomalous scaling of passive scalar fields advected by the Navier-Stokes velocity ensemble: Effects of strong compressibility and large-scale anisotropy
- Resonant enhanced diffusion in time dependent flow
- Pair separation of magnetic elements in the quiet Sun
- Diffusiophoresis, Batchelor scale and effective Péclet numbers
- Eddy diffusivities of inertial particles under gravity
- The assembly of freely moving rigid fibers measures the flow gradient tensor
- A Computational Study of Residual KPP Front Speeds in Time-Periodic Cellular Flows in the Small Diffusion Limit
- Dispersion of passive tracers in velocity field with non delta-correlated noise
- Temporal chaos versus spatial mixing in reaction-advection-diffusion systems
- Many wrong models approach to localize an odor source in turbulence with static sensors
- Large-scale effects on meso-scale modeling for scalar transport
- Anomalous diffusion for inertial particles under gravity in parallel flows
- Effective transport by 2D turbulence: Vortex-gas theory vs. scale-invariant inverse cascade
- Convective plan-form two-scale dynamos in a plane layer
- Local log-law of the wall: numerical evidences and reasons
- Coarse-grained description of a passive scalar
- Combined role of molecular diffusion, mean streaming and helicity in the eddy diffusivity of short-correlated random flows
- Eddy diffusivity in convective hydromagnetic systems
- Generalization of Taylor's formula to particles of arbitrary inertia
- Mean-field equations for weakly nonlinear two-scale perturbations of forced hydromagnetic convection in a rotating layer
- Eddy diffusivity of quasi-neutrally-buoyant inertial particles
- Renormalized transport of inertial particles in surface flows
- Settling velocity of quasi-neutrally-buoyant inertial particles
- Effective Equations in complex systems: from Langevin to machine learning