Background The blood flow through aortic coarctations can undergo transition to turbulence, as the narrowing causes the velocity to increase. Increased levels of turbulent kinetic energy (TKE) are undesirable, as energy is drawn from the mean flow to the turbulent fluctuations. It has recently been shown that TKE in blood flow can be measured with MRI [1], and the aim of this study is to assess...

This is a summary of ve lectures delivered at the CIME course on "Advanced Numerical Approximation of Nonlinear Hyperbolic Equations" held in Cetraro, Italy, on June 1997. Following the introductory lecture I | which provides a general overview of approximate solution to nonlinear conservation laws, the remaining lectures deal with the speciics of four complementing topics: Lecture II. Finite-d...

India : Its Prevalence, Causation and Ijr?ve;ntion. By Arthur Lankester, m.d. (Lond.). .Messrs. Butterworth & Co. Dr. Lanki^stijr's book represents the results of a large amount of laborious and systematic research. It is so full of interesting and useful information that it is difficult to summarise it. The book is divided into the three parts mentioned in the title; it is tke outcome of two y...

We report simulation results for turbulent magnetic reconnection obtained using a newly developed Reynolds-averaged magnetohydrodynamics model. We find that the initial Harris current sheet develops in three ways, depending on the strength of turbulence: laminar reconnection, turbulent reconnection, and turbulent diffusion. The turbulent reconnection explosively converts the magnetic field ener...

A numerical study based on the Eulerian-Lagrangian formulation is performed for dispersed phase motion in a turbulent flow. The effect of spatial filtering, commonly employed in large-eddy simulations, and the role of the subgrid scale turbulence on the statistics of heavy particles, including preferential concentration, are studied through a priori analysis of DNS of particle-laden forced isot...

We present a cascade model for turbulence in weakly collisional plasmas that follows the nonlinear cascade of energy from the large scales of driving in the MHD regime to the small scales of the kinetic Alfvén wave regime where the turbulence is dissipated by kinetic processes. Steady-state solutions of the model for the slow solar wind yield three conclusions: (1) beyond the observed break in ...

We study energy transfer in unbounded Charney-Hasegawa-Mima and surface quasigeostrophic turbulence. The possible inverse-cascading quantities in these systems are, respectively, I identical with integral ( infinity )(0)k(-2)E(k) dk and J identical with integral ( infinity )(0)k(-1)E(k) dk, where E(k) is the kinetic energy spectrum. The supposed direct-cascading quantities for both surface quas...

We review recent results obtained in [14] on weak turbulence of shear-Alfvén waves in the limit of strongly anisotropic pulsations that are elongated along a strong external magnetic field. The kinetic equation for energy is presented at the level of three-wave interactions. It is in agreement with the Galtier et al. [13] formulation of the full three–dimensional helical case when taking the pr...

Experimentally observed anisotropic ion heating in helicon plasma sources may result from the interaction of ions with ion-sound turbulence. The ion-sound turbulence develops due to excitation of the short scale, kinetic, parametric ion-sound instability. From the quasilinear equation for the ion distribution function, which includes the induced scattering of ion-sound waves by ions, the turbul...

This paper presents a new dynamic one equation eddy viscosity model for LES of compressible flows. Based on the compressible version of dynamic Smagorinsky model (DSM), the transport equation for sub-grid scale (SGS) kinetic energy (KE) is introduced to predict SGS KE, instead of the commonly used Yoshizawa’s model. The SGS KE transport equation for compressible flow is derived, and the unclose...