it has been revealed that the surface stress effect plays an important role in the mechanical behavior ofstructures (such as bending, buckling and vibration) when their dimensions are on the order ofnanometer. in addition, recent advances in nanotechnology have proposed several applications fornanoscale shells in different fields. hence, in the present article, within the framework of surfaceel...

With speed increasing in high-speed trains, due to limitations of other types of brakes, aerodynamic brake has become an important braking method. In this task to make better use of brake’s panel different configurations are examined and the best panel shape which provides the reasonable drag coefficient is introduced. The results of simulations are carried out with the computational fluid dyna...

Computational Fluid Dynamics (CFD) is used to predict natural ventilation flows in an enclosure with upper and lower openings connected to the environment. The natural driving forces are wind combined with buoyancy. CFD simulations were carried out by varying the strengths of buoyancy under a constant assisting wind effect. Simulation results of the volume flow rates through the enclosure, the ...

Buoyancy-driven displacement natural ventilation in a simple multi-storey building structure is investigated. The storeys are connected to a common atrium and top-down-chimneys, and the internal heat gains of the storeys are represented by localised point heat sources on each floor. The heat sources generate thermal plumes which entrain the surrounding air and transport warm air upwards. Simple...

Wind catchers are traditional natural ventilation systems attached to buildings in order to ventilate the indoor air. The most common type of wind catcher is four sided one which is capable to catch wind in all directions. CFD simulation is the perfect way to evaluate the wind catcher performance. The accuracy of CFD results is the issue of concern, so sensitivity analyses is crucial to find ou...

The present paper investigates the case of an airfoil placed in a turbulent jet. The Reynolds number based on the chord length is equal to 36,000 and the Mach number to 0.04. The unsteady, threedimensional incompressible flow around the airfoil is first computed with the LES module of the commercial solver FLUENT. An innovative procedure is then proposed to compute from the CFD computation, the...

This paper first presents the architecture of a frequency synthesizer which can support multistandard wireless systems of GPS, Galileo, and WCDMA standards. Then, a programmable integer/fractional combined frequency divider (CFD), which is the key building block of the proposed frequency synthesizer, is designed and implemented by using 0.18μm RF CMOS process. The CFD mainly consists of an inte...

Abstract One of the concerns regarding numerical simulation floating wind turbines (FWTs) in waves is underprediction resonant responses low-frequency range. In present work, difference-frequency wave loads on a restrained semi-submersible FWT subject to bichromatic are investigated by higher-fidelity tools (Computational Fluid Dynamics, CFD) and simplified engineering based potential flow theo...

The main aim of the Computational Fluid Dynamics (CFD) simulations is to reconstruct the reality of fluid motion and behaviour as accurately as possible in order to better understand the natural phenomena under specified conditions. Ideally, general solutions can also cover different scales and geometric configurations. Unfortunately, due to expensive algorithms, classic CFD codes most often re...

Natural ventilation is a commonly applied way in building engineering to ensure a healthy and comfortable indoor climate. In this paper CFD simulations of the natural ventilation of a large semi-enclosed stadium in the Netherlands are described. Simulations are performed to assess the air exchange rate for a total of eight wind directions. The CFD model consists of both the complex stadium geom...