It is shown that collisional plasma transport is intrinsically ambipolar only in quasiaxisymmetric or quasihelically symmetric magnetic configurations. Only in such fields can the plasma rotate freely, and then only in the direction of quasisymmetry. In a non-quasi-symmetric magnetic field, the average radial electric field is determined by parallel viscosity, which in turn is usually governed ...

Use of laminar flow-derived power law models to predict hemolysis with turbulence remains problematical. Flows in a Couette viscometer and a capillary tube have been simulated to investigate various combinations of Reynolds and/or viscous stresses power law models for hemolysis prediction. A finite volume-based computational method provided Reynolds and viscous stresses so that the effects of a...

The k v model has been investigated to quantify its predictive performance on two high lift con gurations D ow over a single element aerofoil involving closed type separation D ow over a prolate spheroid involving open type separation A code friendly modi cation has been proposed which enhances the numerical stabil ity in particular for explicit and uncoupled ow solvers As a result of introduci...

The derivation of the space averaged Navier–Stokes equations for the large eddy simulation (LES) of turbulent incompressible ows introduces two groups of terms which do not depend only on the space averaged ow eld variables: the divergence of the Reynolds stress tensor and commutation errors. Whereas the former is studied intensively in the literature, the latter terms are usually neglected. Th...

A mechanism for turbulent acceleration of parallel rotation is discovered using gyrokinetic theory. This new turbulent acceleration term cannot be written as a divergence of parallel Reynolds stress. Therefore, turbulent acceleration acts as a local source or sink of parallel rotation. The physics of turbulent acceleration is intrinsically different from the Reynolds stress. For symmetry breaki...

In this paper, an investigation into the effect of explicit non-linear turbulence modelling on anisotropic flows is presented. Such are typified in corner separations turbomachinery. The commonly used Reynolds-Averaged Navier-Stokes (RANS) closures, which Reynolds stress tensor modelled by Boussinesq (linear) constitutive relation with mean strain-rate tensor, often struggle to predict separati...

Numerical predictions of blood flow patterns and hemodynamic stresses in Abdominal Aortic Aneurysms (AAAs) are performed in a two-aneurysm, axisymmetric, rigid wall model using the spectral element method. Homogeneous, Newtonian blood flow is simulated under steady conditions for the range of Reynolds numbers 10 < or =Re < or =2265. Flow hemodynamics are quantified by calculating the distributi...

For H-type transition to turbulence in a flat-plate boundary layer, we identify dynamically important features resulting from direct numerical and large eddy simulations (DNS and LES, respectively). Even though LES coupled with a dynamic subgrid-scale model provides an accurate prediction of the transition location, it fails to predict initial overshoot and subsequent turbulent skin friction. D...

The main long-term goal of the project is two-fold: to further develop a new venue in modeling of turbulent mixing using a new spectral theory of turbulence, the quasi-normal scale elimination (QNSE), and to improve the nowcasts and forecasts of the state of the ocean on sub-mesoand mesoscales. The QNSE theory brings turbulence modeling to a new level as it allows one to obtain analytical resul...

Rayleigh-Bernard convection offers a unique flow situation in which buoyancy-generated turbulence can be studied in isolation, free of the complicating influence of shear production of turbulence. The objective of this paper is to examine and model important aspects of buoyancy-generated turbulence using direct numerical simulation (DNS) data of Rayleigh-Bernard convection. In particular, we ex...