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The rational large eddy simulation (RLES) model is applied to turbulent channel flows. This approximate deconvolution model is based on a rational (subdiagonal Pade') approximation of the Fourier transform of the Gaussian filter and is…

Numerical Analysis · Mathematics 2025-10-20 T. Iliescu , P. Fischer

Investigations of the inverse cascade of magnetic helicity are conducted with pseudospectral, three-dimensional direct numerical simulations of forced and decaying incompressible magnetohydrodynamic turbulence. The high-resolution…

Solar and Stellar Astrophysics · Physics 2013-09-23 Wolf-Christian Müller , Shiva Kumar. Malapaka

We study the dependence of turbulent transport coefficients, such as the components of the $\alpha$ tensor ($\alpha_{ij}$) and the turbulent magnetic diffusivity tensor ($\eta_{ij}$), on shear and magnetic Reynolds number in the presence of…

Astrophysics · Physics 2009-03-03 Dhrubaditya Mitra , Petri J. Käpylä , Reza Tavakol , Axel Brandenburg

We perform a mean-field analysis of the EULAG-MHD millenium simulation of global magnetohydrodynamical convection presented in Passos et al. 2014. The turbulent electromotive force operating in the simulation is assumed to be linearly…

Solar and Stellar Astrophysics · Physics 2016-04-07 C. Simard , P. Charbonneau , C. Dube

The Thomas-Fermi (TF) approximation for the static dielectric constant of a three-dimensional electron liquid can be derived from minimizing the TF local-density approximation for the kinetic-energy functional. Here we show that this…

Materials Science · Physics 2009-11-11 A. P. Favaro , Joao Vitor Batista Ferreira , K. Capelle

By taking into account the effect of toroidal magnetic field and its correspond heating, we determine the thickness of advection-dominated accretion flows. We consider an axisymetric, rotating, steady viscous-resistive, magnetized accretion…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Maryam Samadi , Shahram Abbassi , Mahdi Khajavi

We investigate exact results of isotropic turbulence in three-dimensions when the pressure gradient is negligible. We derive exact two-point correlation functions of density in three-dimensions and show that the density-density correlator…

High Energy Physics - Theory · Physics 2009-10-30 A. R. Rastegar , M. R. Rahimi Tabar , P. Hawaii

Standard diffuse approximations of the Willmore flow often lead to intersecting phase boundaries that in many cases do not correspond to the intended sharp interface evolution. Here we introduce a new two-variable diffuse approximation that…

Analysis of PDEs · Mathematics 2019-11-01 Andreas Rätz , Matthias Röger

We present a dynamical spectral model for Large Eddy Simulation of the incompressible magnetohydrodynamic (MHD) equations based on the Eddy Damped Quasi Normal Markovian approximation. This model extends classical spectral Large Eddy…

Fluid Dynamics · Physics 2009-11-13 J. Baerenzung , H. Politano , Y. Ponty , A. Pouquet

Dynamic mode decomposition (DMD) represents an effective means for capturing the essential features of numerically or experimentally generated flow fields. In order to achieve a desirable tradeoff between the quality of approximation and…

Fluid Dynamics · Physics 2014-12-11 Mihailo R. Jovanović , Peter J. Schmid , Joseph W. Nichols

The transport induced by ocean mesoscale eddies remains unresolved in most state-of-the-art climate models and needs to be parameterized instead. The natural scale separation between the forcing and the emergent turbulent flow calls for a…

Fluid Dynamics · Physics 2023-05-31 Julie Meunier , Benjamin Miquel , Basile Gallet

Decaying electron magnetohydrodynamic (EMHD) turbulence in three dimensions is studied via high-resolution numerical simulations. The resulting energy spectra asymptotically approach a k^{-2} law with increasing R_B, the ratio of the…

Plasma Physics · Physics 2015-05-13 C. J. Wareing , R. Hollerbach

This study addresses the well-posedness of a hemivariational inequality derived from the convective Brinkman-Forchheimer extended Darcy (CBFeD) model in both two and three dimensions. The CBFeD model describes the behavior of incompressible…

Analysis of PDEs · Mathematics 2025-09-12 Manil T. Mohan

Initial results from the Madison Dynamo Experiment provide details of the inductive response of a turbulent flow of liquid sodium to an applied magnetic field. The magnetic field structure is reconstructed from both internal and external…

Plasma Physics · Physics 2007-05-23 M. D. Nornberg , E. J. Spence , R. D. Kendrick , C. M. Jacobson , C. B. Forest

We consider a 2D incompressible and electrically conducting fluid in the domain $\mathbb{T}\times\mathbb{R}$. The aim is to quantify stability properties of the Couette flow $(y,0)$ with a constant homogenous magnetic field $(\beta,0)$ when…

Analysis of PDEs · Mathematics 2023-08-25 Michele Dolce

We present results from the first 3D kinetic numerical simulation of magnetorotational turbulence and dynamo, using the local shearing-box model of a collisionless accretion disc. The kinetic magnetorotational instability grows from a…

High Energy Astrophysical Phenomena · Physics 2016-12-07 Matthew W. Kunz , James M. Stone , Eliot Quataert

This study deals with the process and benefits of generating aerodynamic indicial-admittance functions with the support of computational fluid dynamics based on the Euler equations. A simple parametric analytical approximation is alongside…

Fluid Dynamics · Physics 2020-01-22 Marcello Righi , Marco berci

We explore the multi-faceted important features of turbulence (e.g., anisotropy, dispersion, diffusion) in the three-dimensional (3D) wavenumber domain ($k_\parallel$, $k_{\perp,1}$, $k_{\perp,2}$), by employing the k-filtering technique to…

Plasma Physics · Physics 2022-11-30 Rong Lin , Jiansen He , Xingyu Zhu , Lei Zhang , Die Duan , Fouad Sahraoui , Daniel Verscharen

We investigate the radial transport of magnetic flux in a thin accretion disc, the turbulence being modelled by effective diffusion coefficients (viscosity and resistivity). Both turbulent diffusion and advection by the accretion flow…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Jerome Guilet , Gordon I. Ogilvie

The noncommutative dipole QED is studied in detail for the matter fields in the adjoint representation. The axial anomaly of this theory is calculated in two and four dimensions using various regularization methods. The Ward-Takahashi…

High Energy Physics - Theory · Physics 2009-11-07 Neda Sadooghi , Masoud Soroush