نتایج جستجو برای: flow structure

تعداد نتایج: 1975571  

Journal: :bulletin of the iranian mathematical society 2014
b. bidabad m. yarahmadi

‎the notion of quasi-einstein metric in physics is equivalent to the notion of ricci soliton in riemannian spaces‎. ‎quasi-einstein metrics serve also as solution to the ricci flow equation‎. ‎here‎, ‎the riemannian metric is replaced by a hessian matrix derived from a finsler structure and a quasi-einstein finsler metric is defined‎. ‎in compact case‎, ‎it is proved that the quasi-einstein met...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

Journal: :Calculus of Variations and Partial Differential Equations 2022

Abstract We study the asymptotic behaviour of a gradient system in regime which driving energy becomes singular. For this gradient-system convergence concepts are ineffective. characterize limiting different way, by proving $$\Gamma $$ Γ -convergence so-called energy-dissipation functional , combines componen...

اشرف السادات شکرباغانی, , علی اکبر بیدختی, ,

 Layered structures in the oceans have always attracted the attention of oceanographers. The formation of these structures have been attributed to phenomena such as double – diffusive convection, internal waves and turbulent modulated mixing .In this paper, the vertical structures of temperature, salinity, density and the layered structure in the middle parts of Caspian Sea have been studied. C...

Journal: :journal of agricultural science and technology 2013
t. zhong l. yaoming w. chenghong

the existing studies of threshing process of combine harvesters adopt the assumption of constant mass, which is contradictory to the phenomenon of separation of grains and short stalks in actual threshing process. therefore, the characteristics of threshing and separation are not accurately described. aiming at this problem, this study established the tangential-longitudinal threshing and separ...

The flow field associated with the passage of the turbulent spot in a 3–D duct with streamline divergence under zero pressure gradients was investigated and displayed as contour plots of the velocity perturbation in plan and elevation view of the spot. It suggests that, streamline divergence has no strong effect on the internal structure of the spot and eddies and their propagation in the downs...

Journal: :مکانیک سیالات و آیرودینامیک 0
بهزاد قدیری دهکردی حامد حوری جعفری عمید خسروداد

prediction of fluid-elastic instability is a great matter of importance in designing cross-flow tube bundles from the perspective of vibration. in the present paper, the threshold of fluid-elastic instability has been numerically predicted via simulation of incompressible, unsteady, and turbulent cross-flow through a tube bundle in a normal triangular arrangement. the conditions of simulation i...

Abstract In this paper, a fuzzy PID with new structure is proposed to solve the load frequency control in interconnected power systems. in this study, a new structure and effective of the fuzzy PID-type Load frequency control (LFC) is proposed to solve the load frequency control in interconnected power systems. The main objective is to eliminate the deviations in the frequency of different area...

In the recent years, due to the hydropower plants environmental problems, hydrokinetic turbine usages has been increased. Using such turbines in rivers modify natural flow-field. In previous studies, impacts of turbine on the flow-field just only in rectangular open-channel is studied. In this work, the effects of hydrokinetic turbine in a straight compound channel has been numerically studied ...

Journal: :iranian journal of science and technology transactions of mechanical engineering 2015
h. shokuhmand f. sangtarash

numerical and experimental analyses are performed on multilouvered fin banks in low and medium reynolds regimes to investigate the effects of dimples and perforations on flow structure and heat transfer capacity. in different reynolds numbers the flow efficiency has been calculated numerically and experimentally by flow visualization method and the results showed that dimples and perforations c...

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