Facilities built in areas affected by earthquake activity, such as tunnels, which have always been an integral part of human life, must withstand both dynamic and static loading. It has led to the need for practical studies on the effects of earthquakes on underground structures and the factors affecting their destruction. For this purpose, in this research, at first different patterns of tunnel’s excavation were investigated and by using Plaxis 2D software and based on Tabas earthquake in Iran, sensitivity analysis on geotechnical parameters of the soil surrounding tunnel such as cohesion, friction angle, unit weight and modulus of elasticity was carried out, and the parameters whose changes have the greatest and least effects on the bending moment changes on the tunnel lining are introduced. The results show that tunnel excavation patterns significantly affect the bending moment, axial forces, displacements, and surface settlement of the tunnel. Often, by dividing tunnel excavation area to small parts, the values of bending moment, axial forces, displacements, and surface settlement of the tunnel decreases in static analysis. Also, outputs of sensitivity analysis on geotechnical parameters of the soil surrounding tunnel showed that modulus of elasticity of the soil surrounding tunnel has the most effect and cohesion changes have the least effect on bending moment induced on tunnel lining..

In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing method.

One of the important issues to be considered in the design of earth dams is seepage. In general, all soils are more or less water to pass through and accept the intrusion Therefore, in most cases follow the flow of water into the embankment dams is inevitable. If you can not control and restrict the flow of water in dams cause problems and adverse effects that sometimes "destruction and failure of the dam will follow. In this study, a comprehensive review has been numerical modeling of a two-dimensional percolation. After the the study has been presented dam and dam of Hamedan Abshineh been thoroughly studied. then, using the finite element method, two-dimensional and three-dimensional seepage analysis, about the dam was conducted and its results with the results of analyzes two-dimensional comparison, the sensitivity analysis carried out after the stage and perform two- and three-dimensional analysis of the impact of various parameters on the amount of leakage is discussed, at the end solutions to deal with this phenomenon in Hamedan Abshineh proposed dam Are. Due to the geometry of the sort of things can be very variable, and since the construction of three-dimensional model is very bulky and time consuming, so in this study, only one block parameters and specific (case study) used Are.All analyzes were carried out in this thesis Isothermal and interaction effects of heat stress on -transformation leak is ignored.

Representation and modeling of economic uncertainty is addressed by different modeling methods, namely stochastic variables and probabilities, interval analysis, and fuzzy numbers, in particular triple estimates. Focusing on discounted cash flow analysis numerical results are presented, comparisons are made between alternative modeling methods, and characteristics of the methods are discussed.

Objective: Advances in microelectromechanical (MEMS) technologies over the past few decades have contributed to the rapid development of a wide range of microfluidic devices with different functionalities. Fluids are driven through microfluidic systems, therefore, in the current research, it is intended to parametrically investigate the effects of the main parameters, namely length, width and angle of attack of valves, piezoelectric length and applied voltage. Method: The approach of the present research is applied and analytical-experimental with numerical simulations where the tensile force is calculated using COMSOL Multiphysics software and the equations are calculated using the fully coupled algorithm in COMSOL Multiphysics. Findings: The results of the present research show that the main parameters significantly affect the performance of the designed micro pump. So that the applied voltage is 400 volts, the angle of attack is 45 degrees and the width of the valves is 6 micrometers, respectively for the piezoelectric length of 4, 2 and 5 mm, the flow rate is 6. 0.6, 9.6 and 16.6 microliters per minute are obtained. For valve widths of 6 and 8 micrometers, optimal attack angles of 60 and 65 degrees, the corresponding flow rates are 11.11 and 5.9 microliters per minute, respectively. Conclusion: Based on the results of the present research and the investigation of the behavior of the micropump and its output flow rate changes in different working conditions, as the length of the valves increases, the flow rate provided increases. Finally, there is a favorable condition for the width and angle of attack of the valves. This optimal width does not depend on the flow speed.

The computer program CA2 (Continuum Analysis, 2-dimensional), which can solve two-dimensional large strain plasticity problems, is used to model pile driving. The strength of the soil is characterized by a Mohr-Coulomb elastic-perfectly plastic model, and a distinct element approach is used to model pile-hammer interaction. Several numerical tests are performed to demonstrate the importance of different parameters involved in pile driving.

Coastal walls (dyke) are one of the methods of protecting the coast against coastal erosion and destructive forces of waves. The purpose of this study is to simulate the wave collision with the coastal dyke and compare the results with the laboratory model. Open FOAM open source software and K-ω SST turbulence model were used to simulate the amount of wave consumed by the coastal dyke. Taking into account the different conditions for modeling, a total of 45 experiments were selected to run the program. modeling was performed in two general conditions with and without structures and for 3 heights of the structure, 3 different positions of the structure and 5 wave heights. The results showed that the absorption of forces has increased compared to the unstructured state and it can be said that the presence of the structure has been able to play a role in the dissipation of wave force up to 10 times compared to the unstructured state. The intensity of force changes in the structure is a function of wave height and this effect decreases with increasing wave height. Under different wave heights, the farther the structure is from the wave generating tank, the less force is applied to the structure.

Gorgan Bay (GB) is a semi-enclosed basin located southeast of the Caspian Sea (CS), Iran. The bay was registered as a biosphere reserve in 1976 and had an international focus on conservation. GB severely suffers from low water quality and water level. A hydrodynamic model was used to determine its general circulation, differences in temperature, water elevation, and current speed. This investigation includes the study of current vectors' profiles and analyzing the effects of rivers and air pressure in the circulation of this water body. The average current speed was determined to be 0.1 m/s through the bay. The lowest and highest temperatures were investigated and were -0.53°C and +36.57°C, respectively. The general circulation is mostly counter-clockwise. Water elevation and temperature inside GB always follow a seasonal sinusoidal pattern. This paper neglects the effects of rivers on GB hydrodynamics due to their insignificance discharge. Also, the air pressure has a profound effect on the water level. Current vectors showed that while current speed inside this water body has decreased in the past decade, the temperature increased by almost 7°C.

In this article, flow through tube banks has been numerically simulated in order to determine flow induced forces. A Cartesian-staggered grid, based on finite-volume method has been implemented. Furthermore, the ghost-cell method in conjunction with great source term technique has been employed, in order to directly enforce no-slip condition on the tubes' boundaries. The accuracy of the solver was validated by simulation of flow in a cavity and also flow over a single circular cylinder. The results are completely compatible with the experiments. Eventually, the flow through two types of unconfined tube banks with different arrangements in low Reynolds numbers were simulated and analyzed. For these tube bundles, the maximum drag and lift coefficients and maximum gap velocities were numerically obtained. The results shows more lift and drag coefficients in first rows. Also, confined tube boundle produces more flow induced forces on the cylinders.