نتایج جستجو برای: model k ε

تعداد نتایج: 2428879  

Journal: :PROCEEDINGS OF THE JAPANESE CONFERENCE ON HYDRAULICS 1988

Journal: :international journal of advanced design and manufacturing technology 0
mahmoud ebrahimi mohamadhosein rouzbahani

in the course of expansion in turbines steam nucleates to become a two-phase mixture, the liquid consisting of a very large number of extremely small droplets carried by the vapor. formation and subsequent behaviour of the liquid lowers the performance of turbine wet stages. the calculations were carried out assuming that the flow is two dimensional, compressible, turbulent and viscous. a class...

Hadi Shams Nia, Kuorosh Hejazi,

The commonly used linear k-ε turbulence model is shown to be incapable of accurate prediction of turbulent flows, where non-isotropy is dominant. Two examples of non-isotropic flows, which have a wide range of applications in marine waters, are saline water flow and the stratified flows due to temperature gradients. These relate to stratification and consequently, variation of density through...

The present article focuses on the evaluation of a first-moment closure model applicable to film cooling flow and heat transfer computations. The present first-moment closure model consists of a higher level of turbulent heat flux modeling in which two additional transport equations for temperature variance kθ and its dissipation rate εθ are ...

The drops are used to control the descents,  stabilize the bed level, and control the upstream water level in sloping channels with less slope than the ground slope. The current study presents a numerical analysis of hydraulic characteristics in the vertical drop using computational fluid dynamics. At first, the laboratory models were used for verification and choosing the best model of turbule...

ژورنال: :تولید محصولات زراعی و باغی 0
علیرضا کشاورزی a. keshavarzi محمدجواد کاظم زاده پارسی m. j. kazemzadeh parsi

ساختار جریان در آبگیرها ساختاری سه بعدی و بسیار پیچیده است. بنابراین کاربرد معادلات یک بعدی و دو بعدی در این نوع جریان ها واقعیت جریان را به اندازه کافی بیان نمی کند. در این پژوهش شبیه سازی عددی جریان منشعب شده از یک کانال اصلی به داخل کانال فرعی با زاویه 45 درجه مورد بررسی قرار گرفت و نتایج به دست آمده با مدل آزمایشگاهی مقایسه شد. در این مطالعه از دو مدل محاسباتی rng k-ε ,standard k-ε برای مدل...

علیرضا کشاورزی, , محمدجواد کاظم زاده پارسی, ,

Flow structure at water intake is very complicated and three-dimensional. Due to this the application of one and two-dimensional equations can not sufficiently explain the flow structure at water intake. In this study, the simulation of flow structure at a 45 degree water intake was investigated numerically and experimentally. Here, the characteristic of separation zone and velocity distributio...

ژورنال: علوم آب و خاک 2006
علیرضا کشاورزی, , محمدجواد کاظم زاده پارسی, ,

Flow structure at water intake is very complicated and three-dimensional. Due to this the application of one and two-dimensional equations can not sufficiently explain the flow structure at water intake. In this study, the simulation of flow structure at a 45 degree water intake was investigated numerically and experimentally. Here, the characteristic of separation zone and velocity distributio...

2012
Sang-Kyu Lee

This analysis investigates the distortion of flow measurement and the increase of cavitation along orifice flowmeter. The analysis using the numerical method (CFD) validated the distortion of flow measurement through the inlet velocity profile considering the convergence and grid dependency. Realizable k-e model was selected and y+ was about 50 in this numerical analysis. This analysis also est...

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