مقالههای A Imani
توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
۱Comparative Investigation of Control Volume Method and Semi– Empirical Method Using Rapid Prediction code
اطلاعات انتشار: دهمین همایش انجمن هوافضای ایران، سال ۱۳۸۹
تعداد صفحات: ۴
The U.S. Air Force Missile DATCOM (97 version) is widely used aerodynamic prediction code. This code predicts aerodynamic forces, moments, and stability derivatives as a function of angle of attack and Mach number for a wide range of axisymmetric and nonaxisymmetric missile configurations. The body configurations in this study include axisymmetric body without wing tail or body tail. This present article describes a two dimensional numerical investigation of subsonic, transonic and supersonic flow regimes around a body in ten different angles of attack with two methods. The Missile Datcom code (MD) is used as a Rapid Prediction code for solving the Compressible Flow. Studies were performing at 0.6, 1 and 1.5 Mach number. At the same conditions the body has been modeled in commercial computations fluid dynamics code –Fluent6.3– with k–ω turbulence model. A structured mesh was adopted to map the flow domain around of body. A finite volume approach has been used and the pressure–velocity coupling is resolved using the SIMPLE algorithm. Lift and drag coefficients of MD solution are compared with the Fluent solution and good trend are obtained. But in the transonic condition – mach 1– the error of result is higher. Based on the results obtained, the MD is better than fluent for this type of studies with significant saving in computational cost, time and simple in operations.<\div>
اطلاعات انتشار: International Journal of Engineering، بيست و پنجم،شماره۳،September ۲۰۱۲ ، سال ۰
تعداد صفحات: ۸
Many researchers have been interested in application of mathematical methods to find analytical solutions of nonlinear equations and for this purpose, new methods have been developed. One of the newest analytical methods to solve nonlinear equations is Reconstruction of variational Iteration Method (RVIM) which is an accurate and a rapid convergence method in finding the approximate solution for nonlinear equations. By applying Laplace Transform, RVIM overcomes the difficulty of the perturbation techniques and other variational methods in case of using small parameters and Lagrange multipliers, respectively. In this study RVIM is applied for the effects of magnetic field and nano particle on the Jeffery–Hamel flow. The traditional Navier–Stokes equation of fluid mechanics and Maxwell’s electromagnetism governing equations are reduced to nonlinear ordinary differential equations to model the problem. The flow field inside the divergent channel is studied for various values of Hartmann number and angle of channel. Finally the effect of nano particle volume fraction in the absence of magnetic field is investigated, too. The validity of RVIM method is ascertained by comparing our results with numerical (Runge Kutta method) results.
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