Motivated by Genzel et al.’s observations of high-redshift star-forming galaxies, containing clumpy and turbulent rings or disks, we build a set of equations describing the dynamical evolution of gaseous disks with inclusion of star formation and its feedback. Transport of angular momentum is due to ”turbulent” viscosity induced by supernova explosions in the star formation region. Analytical s...

this paper presents the effect of high viscosity oil and two-phase foamy-oil flow on the performance of a single stage centrifugal pump. as a part of this, the applicability of a pipe viscometer to determine the foamy oil viscosity is investigated. unlike previous studies, a sealed fluid tank is used in a closed flow loop to allow conditioning the two-phase mixture to create foamy-oil. furtherm...

The natural convection flow phenomena that occur inside an enclosed space are very interesting examples of complex fluid systems that may yield to analytical, empirical and numerical solutions, and many reports have looked into this basic problem. In the present study, heat transfer and fluid flow for natural convection in a horizontal rectangular container with a free surface are investigated ...

natural gas is one of the hydrocarbon resources which is consumed vastly in the world. the asian and european markets, facing with a growing demand of hydrocarbon resources especially natural gas, are the most important consuming markets. hence, the security of natural gas supply is very important. based on the estimation of gas supply security index (gssi), the amount of vulnerability of selec...

gas compressibility factor (z-factor) is an important parameter widely applied in petroleum and chemical engineering. experimental measurements, equations of state (eoss) and empirical correlations are the most common sources in z-factor calculations. however, these methods have serious limitations such as being time-consuming as well as those from a computational point of view, like instabilit...

â â â â â â â â  abstract â  this work was supported by the academy of korean studies of the republic of korea in year 2012-2013 (aks-2010-caa-2101) energy security has assumed newfound geopolitical importance at the outset of xxi century (moran and russell, 2008). diminishing fossil fuel supplies have led to fears of energy shortages, while rapid economic and population growth have fuelled the...

reduction of exhaust emissions is a major research task in diesel engine development in view of increasing concerns regarding environmental protection and stringent exhaust gas regulations. simultaneousreduction of nox emissions and particulate matter is quite difficult due to the soot/nox trade-off and isoften accompanied by fuel consumption penalties. towards this aim, automotive engineers ha...

We analyze a mathematical model for the relaxation of translational and internal temperatures in a nonequilibrium gas. The system of partial differential equations—derived from the kinetic theory of gases—is recast in its natural entropic symmetric form as well as in a convenient hyperbolic-parabolic symmetric form. We investigate the Chapman-Enskog expansion in the fast relaxation limit and es...