environmental noise pollution is among the most urban problems which can be caused due to real sources like traffic, train and virtual sources provided by rigid surfaces. one of the urban structures in which can perform as a virtual noise source are the installed gutters alongside highways. these structures are mostly used to pass the wastewater or the rainfall. in this research, the acoustical...

Designing and manufacturing the multiple jets simulator and experimental investigation of the multiple jets in crossflow at low velocity ratios have been studied Together with design and build a low-speed wind tunnel. A specific rake is used to determine the flow field pressure and changes in static pressure measured by pressure taps in the near field of the jets. There are generally three regi...

Designing and manufacturing the multiple jets simulator and experimental investigation of the multiple jets in crossflow at low velocity ratios have been studied Together with design and build a low-speed wind tunnel. A specific rake is used to determine the flow field pressure and changes in static pressure measured by pressure taps in the near field of the jets. There are generally three regi...

Using heat shield, especially in throat area has a significant effect on combustion chamber pressure and thermal efficiency of solid fuel engines. Precise prediction of the regression of throat area for different pressures, will lead to optimal design of the motors, specifically for those of long burnout times. In this work, erosion of graphite nozzles employed in solid propellant motors with a...

Bend existence induces changes in the flow pattern, velocity profiles and water surface. In the present study, based on experimental data, first three-dimensional computational fluid dynamic (CFD) model is simulated by using Fluent two-phase (water + air) as the free surface and the volume of fluid method, to predict the two significant variables (velocity and channel bed pressure) in 90º sharp...

the quality of pressure distribution over the atmosphere of the sea level and geopotential altitude at different atmosphere layers affect on many climate and meteorology phenomena of the earth surface. one of the important meteorology phenomenon is the occurrence of frost phenomenon especially late spring frost. in this surrey, occurring late spring frost days and minimum temperature during the...

low temperature plasma technology is well established in surface modification of polymer materials on industrial scale. this method modifies surface properties of polymers without chemicals, manual work and reducing chemicals and energy consumption. in this study, low pressure plasma treatment was used to develop hydrophilic properties of polyethylene terephthalate (pet) fabrics. it was found t...