One of the most interesting problems in fluid dynamics is the prediction of particleladen turbulent flows. These flows are as diverse as pollutant dispersion in the atmosphere and contaminant transport in industrial applications. An issue of primary importance for moderately dense suspensions concerns how particles affect the turbulent flow itself, the so-called two-way coupling. It is known th...

با توجه به الزامات زیست‌محیطی، اجتماعی و اقتصادی، طراحی شبکه زنجیره تأمین حلقه‌­بسته پژوهشگران زیادی را خود جذب کرده است. این مسئله بیشتر به‌صورت مجزا از ارزیابی تأمین‌کنندگان موردمطالعه قرار گرفته عوامل مختلفی به‌جز قیمت مانند ویژگی‌های تأمین‌کننده قطعه می‌تواند تأثیر بر عملکرد داشته باشد. در پژوهش یک شامل سایت‌های تولید، جداسازی، بازسازی دفع نظر مدلی تلفیقی سه مرحله ارائه شده نخست روش ترکیبی ...

در این مقاله حل دقیق ارتعاش برون صفحه‌ای نانو ورق‌های مستطیلی نسبتاً ضخیم براساس تئوری غیر‌محلی تغییر شکل برشی سینوسی اصلاح شده با نظر گرفتن شرایط مرزی لوی ارائه است. هدف اصلی تحقیق بررسی اثر مقیاس کوچک بر پارامترهای فرکانسی می‌باشد. برای توصیف تأثیرات خارج از صفحه‌ی ورق غیر محلی ارینگن استفاده شده. مشتمل شش حالت مختلف شامل دو ضلع موازی دارای تکیه‌گاه ‌ساده و اضلاع دیگر ترکیبی ساده، گیردار آزاد ...

Flow field around hypersonic vehicles is very complex and difficult to simulate. The boundary layers are squeezed between shock layer and body surface. Resolution of boundary layer, shock wave and turbulent regions where the flow field has high values is difficult of capture. Detached eddy simulation (DES) is a modification of a RANS model in which the model switches to a subgrid scale formulat...

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 ...

To bridge the gap between high and low fidelity numerical modeling tools for vertical-axis (or cross-flow) turbines (VATs or CFTs), an actuator line model (ALM) was developed and validated for both a high and a medium solidity vertical-axis turbine at rotor diameter Reynolds numbersReD ∼ 10. The ALM is a combination of classical blade element theory and Navier–Stokes based flow models, and in t...

Lagrangian averaging (LA) is producing new ideas and methods for the construction of novel subgrid models for momentum, energy and scalar transport in turbulence. LA is applied at fixed Lagrangian fluid label, rather than at fixed spatial location, as in Eulerian averaging and filtering for RANS and LES equations, respectively. Instead, LA is performed in a frame of motion that follows along wi...

This thesis covers two main topics. The first is the comparison between the Reynoldsaveraged Navier-Stokes (RANS) simulation and the Large Eddy Simulation (LES) of high injection pressure diesel sprays under non-evaporating or evaporating conditions. The second topic is the comparison of the fuel behavior in the spray process between the hydrotreated vegetable oil (HVO) and the conventional EN ...

Hybrid RANS/LES models, capable of transitioning through arbitrary levels modeled and resolved turbulence, aim to ameliorate both RANS deficiencies LES expense. We propose a method combining active forcing the flow field, where appropriate, with splitting standard single turbulence model into separate responsible for either unresolved stress or dissipation, which adapts that $i\phantom{\rule{0}...