نتایج جستجو برای: spalart
تعداد نتایج: 203 فیلتر نتایج به سال:
An adjoint-based Navier-Stokes design and optimization method for two-dimensional multi-element high-lift configurations is derived and presented. The compressible Reynolds-Averaged Navier-Stokes (RANS) equations are used as a flow model together with the Spalart-Allmaras turbulence model to account for high Reynolds number effects. Using a viscous continuous adjoint formulation, the necessary ...
Large-eddy simulation (LES) has been used to predict the statistically threedimensional turbulent boundary layer (3DTBL) over a rotating disk. LES predictions for six parameter cases were compared to the experimental measurements of Littell & Eaton (1994), obtained at a momentum thickness Reynolds number of 2660. A signaldecomposition scheme was developed by modifying the method of Spalart (198...
An adjoint-based Navier-Stokes design and optimization method for two-dimensional multi-element high-lift configurations is derived and presented. The compressible Reynolds-Averaged Navier-Stokes (RANS) equations are used as a flow model together with the Spalart-Allmaras turbulence model to account for high Reynolds number effects. Using a viscous continuous adjoint formulation, the necessary ...
This paper presents computational results for two DES (Detached Eddy Simulation), one hybrid RANS (Reynolds Averaged Navier-Stokes)/ LES (Large Eddy Simulation) and some preliminary results from PANS (Partially Averaged Navier-Stokes) turbulence for simulation of unsteady separated turbulent flows. The models are implemented in a full 3-D Navier Stokes solver and are based on the twoequation k-...
Large Eddy Simulation (LES) and Reynoldsaveraged Navier-Stokes (RANS) calculations have been used to predict the development, separation, reattachment and downstream recovery of the flow over a smoothly contoured ramp. The statistically two-dimensional upstream flow separates along the ramp surface and then reattaches downstream on a flat section. A canonical flatplate turbulent boundary layer ...
پدیده های آیرودینامیک غیردائم بیشتر بر روی پره های هلی کوپتر، توربین های بادی، میکرو پرنده ها، پره های کمپرسور و حتی بال حشرات رخ می دهد. بررسی جریان غیردائم از آنجایی که در زاویه های حمله بالا عامل محدود کننده کارکرد پره های هلی کوپتر و توربین های بادی است، از اهمیت زیادی برخوردار است. چه بسا در اکثر مواقع نیروهای حاصل از جریان غیردائم بیشتر از جریان دائم بوده و از اثرات آن نمی توان صرفنظر کرد...
Numerical simulations are performed of the turbulent flow and thermal field in a structured porous media. The geometry of interest is an open lattice structure that is made up of mutually orthogonal, millimeter-scale, thermally conductive cylindrical elements. A large-eddy simulation (LES) is performed and the results are used as reference data to evaluate the performance of three commonly used...
هدف این پژوهش بهینه سازی عملگر جت مصنوعی برای کنترل جریان حول ایرفویل naca0015، در دو زاویه حمله 13 درجه (زاویه حمله واماندگی برای ایرفویل naca0015) و زاویه حمله 16 درجه (زاویه حمله پس از واماندگی)، برای بیشینه کردن عملکرد آیرودینامیکی ایرفویل، می باشد. عملگر جت مصنوعی، وسیله ای با شار جرمی صفر برای کنترل فعال جریان است که براساس فرکانس ورودی، به صورت نوسانی به مکش و دمش جریان از دهانه کوچک خود...
Robust design optimization involves finding the loworder statistical moments, i.e. the maximization of some mean quantity of interest and minimization of its variance. The question arises as to when a mean or variance value can be considered to be converged to an acceptable level of certainty. A designer naturally seeks to keep the number of function evaluations as low as possible when convergi...
No AccessTechnical NotesLighthill Stress Flux Model for Ffowcs Williams–Hawkings Integrals in Frequency DomainZhiteng Zhou, Hongping Wang, Shizhao Wang and Guowei HeZhiteng ZhouState Key Laboratory of Nonlinear Mechanics, Chinese Academy Sciences, 100190 Beijing, People’s Republic China*Ph.D. Candidate, Institute Mechanics; also School Engineering University 100049 China.Search more papers by t...
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