This article, by leaving pre-determined membership function of a fuzzy set which is a basic assumption for such subject, will try to propose a hybrid technique to select the most economic project among alternative projects in fuzziness interest rates condition. In this way, net present worth (NPW) would be the economic indicator. This article tries to challenge the assumption of large sample si...

premixed combustion is widely used for reducing pollutant emission from combustion chambers. however, these systems may be sensitive to complex phenomena such as flashback. in the present study flame, flashback and structure of premixed laminar flames are investigated theoretically. the mathematical model includes the axi-symmetric continuity, navier stocks, energy, and species equations. combu...

in this paper, the flow around bluff bodies with different cross sections and determination of forces acts on them are investigated.this paper presents the results of a numerical study on the flow characteristics and heat transfer over two equal square cylinders in a tandem arrangement. spacing between the cylinders is 5 widths of the cylinder and the reynolds number ranges from 1 to 200, pr=0....

cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. however, the main weakness of cylindrical tubes is in the high initial peak load. therefore, in this paper, to overcome this weakness, a buckling initiator is used at the top of the tube. this buckling initiator is a steel rod...

Numerical simulation in aluminum production envolves many different topics, this paper is dedicated to some aspects of two of them. In the first part, a numerical approach for the computation of the motion of the fluids in an electrolitic cell is presented, with an emphasis on a mesh deformation technique to track the free interface during the time. In a second part, a model for the simulation ...

Most of the Iranian oil and gas wells in the Persian Gulf region are producing through their natural productivity and, in the near future, the use of stimulation methods will be undoubtedly necessary. Hydraulic fracturing as a popular technique can be a stimulation candidate. Due to the absence of adequate research in this field, numerical simulation can be an appropriate method to investigate ...

in recent years, the number of research works devoted to applying the highly accurate numerical schemes, in particular compact finite difference schemes, to numerical simulation of complex flow fields with multi-scale structures, is increasing. the use of compact finite-difference schemes are the simple and powerful ways to reach the objectives of high accuracy and low computational cost. compa...

The main aim of this study, is to evaluate the seismic reliability of steel concentrically braced frame (SCBF) structures optimally designed in the context of performance-based design. The Monte Carlo simulation (MCS) method and neural network (NN) techniques were utilized to conduct the reliability analysis of the optimally designed SCBFs. Multi-layer perceptron (MLP) trained by back propagati...

the liquid metal flow and the solidification behaviours in a multi-cavity casting mould of two automotive cast parts were simulated in three dimensions. the commercial code, flow-3d® was used because it can track the front of the molten metal by a volume of fluid (vof) method and allows complicated parts to be modeled by the fractional area/volume obstacle representation (favor) method. the gre...