This is the first of a series of papers aimed at developing and interpreting simulations of protoplanets interacting with turbulent accretion discs. In this first paper we study the turbulent disc models prior to the introduction of a perturbing protoplanet. We study cylindrical disc models in which a central domain is in Keplerian rotation and unstable to the magnetorotational instability (MRI...

This paper represents the results of an experimental work with measurement of mean velocity along with total pressure contours in 2-D form and validation of the same with numerical results based on the wall y + approach for various turbulent models like, Spalart Alamras, k-ε model, k-ω model and RSM models are used to solve the closure problem. The turbulence models are investigated in the comm...

Turbulence closure models are evaluated for application to spilling and plunging breakers in the surf zone using open source computational fluid dynamics software. A new library of turbulence models for application to multiphase flows has been developed and is assessed for numerical efficiency and accuracy by comparing against existing laboratory data for surface elevation, velocity and turbule...

Turbulent transport of material inclusions plays an important role in many natural and industrial situations. Being able to accurately model and predict the dynamics of dispersed particles transported by a turbulent carrier flow, remains a challenge. One critical and difficult point is to develop models which correctly describe the dynamics of particles over a wide range of sizes and density. O...

Floods, tides and tsunamis are turbulent, yet conventional models are based upon depth averaging inviscid irrotational flow equations. We propose to change the base of such modelling to the Smagorinksi large eddy closure for turbulence in order to appropriately match the underlying fluid dynamics. Our approach allows for large changes in fluid depth to cater for extreme inundations. The key to ...

The origins of solar magnetism lie below the visible surface of the Sun, in the highly turbulent convection zone. Turbulent convection operates in conjunction with rotational shear, global circulations and intricate boundary layers to produce the rich diversity of magnetic activity we observe. Here, we review recent insights into the operation of the solar dynamo obtained from solar and stellar...

the thermo-hydraulic behavior of the air flow over a two dimensional ribbed channel wasnumerically investigated in various rib-width ratio configurations (b/h=0.5-1.75) atdifferent reynolds numbers, ranging from 6000 to 18000. the capability of differentturbulence models, including standard k-ε, rng k-ε, standard k-ω, and sst k-ω, inpredicting the heat transfer rate was compared with the experi...

We give a status report of convective Cepheid and RR Lyrae model pulsations. Some striking successes can be reported, despite the use of a rather simple treatment of turbulent convection with a 1D time-dependent diffusion equation for the turbulent energy. It is now possible to obtain stable double-mode (beat) pulsations in both Cepheid and RR Lyrae models with astrophysical parameters, i.e. pe...

We consider the inverse mean curvature flow in RobertsonWalker spacetimes that satisfy the Einstein equations and have a big crunch singularity and prove that under natural conditions the rescaled inverse mean curvature flow provides a smooth transition from big crunch to big bang. We also construct an example showing that in general the transition flow is only of class C.

in the present work a two dimensional numerical investigation of steam flows in a turbine blade passage is performed. a finite volume approach has been used and the pressure–velocity coupling is resolved using the simple algorithm. the purpose of this paper is to find that one of the used turbulent models is better for this kind of studies. a structured mesh arrangement with boundary layer mesh...