in order to present a quantitative indicator for the onset of instability, in this paper, the critical points of a stratified gravitational flow on a slope are found and analyzed. these points are obtained by means of the solution of the two-dimensional navier-stokes equations via the standard arakawa-c finite-difference method. results show that in the marginal richardson numbers, the critical...

introduction air pollution has harmful effect on human health and the environment. accordingly, considerable effort has been put to analyze the air pollutants. one important issue is the spatial distribution of these pollutants. dispersion of the pollutants released from sources on the ground is mostly driven by the planetary boundary layer where turbulent flow causes mixing of the content of t...

This paper is concerned with asphaltene deposition in fluid flowing through pipelines. Brownian diffusion and drag, gravitational, thermophoresis, buoyancy, and shear removal are considered as possible mechanisms in the asphaltene deposition process. The thermo-physical properties of the fluid were obtained from Iranian oil fields. A model was used in the pipeline deposition modeling to predict...

this paper is concerned with asphaltene deposition in fluid flowing through pipelines. brownian diffusion and drag, gravitational, thermophoresis, buoyancy, and shear removal are considered as possible mechanisms in the asphaltene deposition process. the thermo-physical properties of the fluid were obtained from iranian oil fields. a model was used in the pipeline deposition modeling to predict...

The gravity water wave black (GWBH) hole analog discovered by Schutzhold and Unruh (SU) is extended to allow for the presence of turbulent shear flow. The Riemannian geometry of turbulent black holes (BH) analogs in water waves is computed in the case of lami-nar tirbulent shear flow. The Riemann curvature is constant and the geodesic deviation equation shows that the curvature acts locally as ...

Field flow fractionation is a family of separation techniques applicable to characterize various particulate materials of different nature. In this paper, formation of porous graphite during milling has been investigated by gravitational field flow fractionation. The results from gravitational field flow fractionation were compared to those from Brunauer-Emmett-Teller. The both techniques have ...

— We consider low angular momentum, neutrino cooled accretion flows onto newborn black holes in the context of the collapsar model for long Gamma Ray Bursts, and find a considerable energy release for rotation rates lower than those usually considered. The efficiency for the transformation of gravitational binding energy into radiation is maximized when the equatorial angular momentum l0 ≃ 2rgc.

Three-dimensional simulations of the disk-halo interaction show the formation of a thick HI and HII gas disk with different scale heights. The thick HI disk prevents the disk gas from expanding freely upwards, unless some highly energetic event such as chimneys occurs, whereas the thick HII disk acts as a diskhalo interaction region from where the hot ionized gas flows freely into the halo. The...

All accretion models of gamma-ray bursts share a common assumption: accretion power and gravitational binding energy is released and then dissipated locally, with the mass of its origin. This is equivalent to the Shakura-Sunyaev 1973 (SS73) prescription for the dissipation of accretion power and subsequent conversion into radiate output. Since their seminal paper, broadband observations of quas...