نتایج جستجو برای: boundary layer

تعداد نتایج: 419428  

The objective of this work is to develop deep theoretical methods that are based on the solution of the integral boundary layer equations for investigating film cooling in liquid rocket engine. The integral model assumes that heat is transferred from hot free stream gas to the liquid film both by convection and radiation. The mass is transferred to the free srteam gas by the well-known blowing ...

This study develops a fuzzy sliding mode controller (FSMC) based on a variable boundary layer. A fuzzy inference mechanism is used to on-line tune the thickness of the boundary layers of the controller. Minimum rule base has been used for the fuzzy inference system which results in low calculation effort. The aim of this paper is to design a controller which will eliminate the chattering of FSM...

Journal: :journal of computational applied mechanics 0
masoud ghasemian department of mechanical engineering, university of tehran, tehran, iran amir nejat department of mechanical engineering, university of tehran, tehran, iran

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-...

Journal: :مکانیک سیالات و آیرودینامیک 0
مهدی صنیعی نژاد عبدالعلی حقیری محمود مانی سجاد درستی

boundary layer growth and hence displacement thickness are the key factors in shock position over aerodynamical surfaces at transonic regimes. since boundary layer growth is a function of free stream reynolds number and also of the transition location, the free stream reynolds number and also the other parameters involved in the boundary layer growth and its transition location are determinant ...

Journal: :مکانیک سیالات و آیرودینامیک 0

in this paper, the accuracy of k- and k- turbulence models in super sonic boundary layer capturing of smooth/rough flat plates have been comprehensively investigated. among these investigations, some sorts of sensitivity analysis, including change in turbulence model, generated-grid density, near wall affects, c magnitude (for boundary layers generated on smooth flat plates), and change in c...

Journal: :international journal of advanced design and manufacturing technology 0
reza amininejad alireza mohajerani alireza samsami shahab amininejad

this work presents free vibration analysis of laminated rectangular plates with classical boundary conditions based on the classical plate theory (cpt). the first involves an s-fgm plate with different boundary conditions. then involves a two-layer plate in which an s-fgm layer is coated on a homogeneous substrate with classical boundary conditions, simply called an s-fgm-coated plate; the othe...

Journal: :فیزیک زمین و فضا 0
مجید مزرعه فراهانی استادیار، گروه فیزیک فضا، مؤسسه ژئوفیزیک دانشگاه تهران، ایران علی جلالی دانشجوی دکتری، دانشکده فیزیک، دانشگاه وسترن اونتاریو، کانادا محمدعلی ثقفی دانش آموخته کارشناس ارشد هواشناسی، گروه فیزیک فضا، مؤسسه ژئوفیزیک دانشگاه تهران، ایران

turbulent fluxes in the atmospheric boundary layer are calculated using different models. one of the most popular and operational models in this groundwork is the second order turbulent model of mellor and yamada that has been widely used to simulate the planetary boundary layer (pbl). despite its popularity, it has been shown that this model has several weeknesses that affect its accuracy. the...

Journal: :international journal of industrial mathematics 2015
n. ‎aliev s. ashrafi a. r. sarakhsi‎

singular perturbation problems have been studied by many mathematicians. since the approximate solutions of these problems are as the sum of internal solution (boundary layer area) and external ones, the formation or non-formation of boundary layers should be specified. this paper, investigates this issue for a singular perturbation problem including a first order differential equation with gen...

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