Sharif Digital Repository

Single-layer steel grid shell structures are a good structural solution to new buildings by specific properties that are required by long-span structures and provide at the same time the opportunity to produce immense verity of design shapes and free form architecture; complex curved surfaces expect to be covered with low weight material. A grid shell is essentially a shell with its structure concentrated into individual linear element in relatively thin grid compared to the overall dimension of the grid shell. This research investigates single-layer grid structures with emphasis on design of load details. The application of single-layer for transparent structures enhances use of glazed... 

Considering atmospheric wave propagation as a complex phenomenon, it can be represented as a function of variety of parameters such as: properties of atmosphere, boundary conditions, surface characteristics, source related parameters and etc. the aim of this work is to study the propagation of sound mechanisms in troposphere layer and numerical simulation of sound field in order to investigate the wind effect and turbulence in wave propagation. In this manner, the Green’s function parabolic equation (GFPE) is hired to solve the governing equation for sound propagation in a moving inhomogeneous atmosphere. To achieve this, a code is generated using MATLAB software to predict the long range... 

According to the climates of the country, using natural draft dry air cooling systems at the power plant is one of the proposed solutions for lower water consumption, but strong wind can make drop in performance of power plant cooling systems based on Rankine Cycle. This means that wind disrupted the order of the normal flow of air intake around the tower by creating areas of low pressure, preventing the flow of air into the cooling system. In the world, many researches and solutions have been proposed to solve the problem. The most common of these solutions is using of windbreaks as aerodynamic devices to compensate for the pressure drop in the cooling tower when the wind blows. But... 

The plant's drag force, in addition to changing the amount of flow velocity within the canopy area, may also alter its structure. In the present study, the aim is to carry out a series of experiments to investigate the energy regime in the exchange flow caused by the phenomenon of surface cooling. In previous studies, the focus was on inertial and viscosity regimes in the lab, while in the present study, about the occurrence of the energy regime in nature, attempts are made to see the energy regime in the laboratory. In this research, PIV technique was used to determine the flow rate in depth. The variation parameters in these studies are the volume percentage of vegetation cover (φ), free...