نتایج جستجو برای: regimes of laminar and turbulent flow

تعداد نتایج: 24098341  

Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer flows. Computational method is based on the solution of the Reynolds averaged Navier-Stokes (RANS) equations and the eddy-viscosity concept. Transitional model tries to simulate streamwise fluctuations, induced by freestream turbulen...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی 1392

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

Journal: :پژوهش های جغرافیای طبیعی 0
سجاد باقری سیدشکری دانشجوی دکتری ژئومورفولوژی دانشکدة جغرافیا، دانشگاه تهران مجتبی یمانی استاد دانشکدۀ جغرافیا، دانشگاه تهران منصور جعفربیگلو دانشیار دانشکدۀ جغرافیا، دانشگاه تهران حاجی کریمی دانشیار دانشکدۀ کشاورزی، دانشگاه ایلام ابراهیم مقیمی استاد دانشکدۀ جغرافیا، دانشگاه تهران

introduction hydrograph of springs represents clearly all physical processes that control ground water flows inside aquifer (kuto et al., 2012: 41). study of the curve can reveal information about structure and function of aquifer, particularly hydrodynamic parameters including permeability and storage (troch et al., 1993: 228). analysis of recession curve has the advantage to calculate paramet...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی علوم پایه زنجان - دانشکده فیزیک 1392

in the first part of this thesis we explored wetting and its dynamics for small droplets. first, we showed how a simple feature of water droplets on a surface, i.e. laplace pressure, can be exploited to build a micropump. we investigated capillary pumping in microchannels both experimentally and numerically. putting two droplets of different sizes at the in/outlet of a microchannel, will ge...

Journal: :international journal of advanced design and manufacturing technology 0
mohammadreza safaiy hamidreza goshayeshi

mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. in this study, first the laminar mixed convection inside rectangular enclosure with moving wall and aspect ratio=10 is modeled and then the results are compared with other investigate. after showing varity of results, the investigation is continued with tur...

2012
Joseph H. Harris Peter J. Thomas Stephen J. Garrett

We consider the effects of distributed roughness on the boundary-layer transition over a rotating disk using both theoretical and experimental approaches. The theoretical approach further develops Yoon et al.’s method [Int. J. Heat Fluid Flow, 28, p262 (2007)] for obtaining the steady-flow solutions for a general surface distribution function. Full threedimentional stability analyses are conduc...

The airflow in the modeled glottal constriction was simulated by the solutions of the Navier-Stokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow in generalized, nonorthogonal coordinates using a numerical method. A two-dimensional model of laryngeal flow is considered and aerodynamic properties are calculated for both laminar and turbulent steady flows...

Journal: :Entropy 2014
Donald M. McEligot Edmond J. Walsh

In an earlier paper in Entropy [1] we hypothesized that the entropy generation rate is the driving force for boundary layer transition from laminar to turbulent flow. Subsequently, with our colleagues we have examined the prediction of entropy generation during such transitions [2,3]. We found that reasonable predictions for engineering purposes could be obtained for flows with negligible strea...

2004
J. H. Nie B. F. Armaly

Laser-Doppler velocity measurements adjacent to the bounding walls of three-dimensional (3-D) backward-facing step flow are performed for the purpose of mapping the boundaries of the reverse flow regions that develop in this geometry (adjacent to the sidewalls, the flat wall and the stepped wall) as a function of the Reynolds number. The backward-facing step geometry is configured by a step hei...

The current study presents the results of the aerodynamic noise prediction of the flow field around a NACA 0012 airfoil at a chord-based Reynolds number of 100,000 and at 8.4 degree angle of attack. An incompressible Large Eddy Simulation (LES) turbulence model is applied to obtain the instantaneous turbulent flow field. The noise prediction is performed by the Ffowcs Williams and Hawkings (FW-...

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