Models of planetary, atmospheric and oceanic circulation involve eddy viscosity and eddy diffusivity, KM and KH , that account for unresolved turbulent mixing and diffusion. The most sophisticated turbulent closure models used today for geophysical applications belong in the family of the Reynolds stress models. These models are formulated for the physical space variables; they consider a hiera...

The solar torsional oscillations are considered as the response of the Reynolds stress to the time-dependent dynamo-induced magnetic eld. This picture is opposite to the so far accepted idea that it is the large-scale Lorentz force which directly drives the temporal variations of the surface rotation proole. Here, the \magnetic quenching" of the components of the Reynolds stress { viscosity ten...

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...

  Unsteady flow separation on the airfoils with local flexible membrane (LFM) has been investigated in transient and laminar flows by the finite volume element method. A unique feature of the present method compared with the common computational fluid dynamic softwares, especially ANSYS CFX, is the modification using the physical influence scheme in convection fluxes at cell surfaces. In contr...

The performance of an explicit algebraic stress model is assessed in predicting the turbulent ow and forced heat transfer in straight ducts, with square, rectangular, trapezoidal and triangular cross sections, under fully developed conditions over a range of Reynolds numbers. Iso-thermal conditions are imposed on the duct walls, and the turbulent heat uxes are modeled by gradient-di usion type ...

The paper presents a low-order prediction scheme for the noise change in multistream jets when the nozzle geometry is altered from a known baseline. The essence of the model is to predict the changes in acoustics due to the redistribution of the mean flow as computed by a Reynolds-Averaged Navier Stokes (RANS) solver. A RANS-based acoustic analogy framework is developed that addresses the noise...