Sharif Digital Repository

Smoothed Particle Hydrodynamics (SPH) is a numerical Lagrangian meshless method which has numerous applications in astrophysics, hydrodynamics, free-surface flows, jets and sprays formation. Atomization of continuum liquid to fine droplets or in other words, liquid breakup processes are emerged in many engineering applications such as fuel sprays inside the combustion chamber of internal combustion engines that sizes of produced sprays significantly influence the engine’s efficiency. This research is accomplished to investigate the one-phase and two-phase flows of liquid jet breakup. For this aim, an open source code called SPHysics which solves the flow field by SPH method is utilized. This... 

In Mechanical systems there is always possibility of statical and dynamical following force. These forces are generated due to aerodynamic pressure, temperature gradient, and jet thrusters. In unstabel systems, if the value of this force exceeds a certaim amount the system becomes unstable. This value is called as critical force. In order to analyse these systems, fisrt of all, the governing dynamic equations are obtained by using the Galerkin-Ritz method. Then, by utilising the modal analysis, these equation are uncoupled. And then, the Ito set of equations are derived. By utilising the Lyapanov method, Ito equations are transfered to another state. and using the fokker-planc equation the... 

Knowledge markets where knowledge transactions take place are today see increasingly expansion by influences of the Internet and the importance of knowledge. A competitive space, thus, has been placed among different enterprises step in knowledge markets. With no exception to this general rule, one of these markets covers online question – answer knowledge market. Google Answers is a proposed website in this area which, although being of interest in recent decades, its activities ended in 2006 for several reasons. Significantly, these markets consist of many factors with interrelated effects on each other and this leads to complexity of systems. Therefore, in order to study these markets, it... 

The design and operation of energy systems infrastructure is typically based on key reliability criteria such as system security and adequacy. Nowaday, with the rise of unexpected events and events such as floods, earthquakes, storms, and other natural phenomena can affect the performance of energy infrastructure. Given the low probability of these events, reliability studies and relevant criteria cannot guarantee that an energy infrastructure can respond well to these events. Investigating the ability of energy infrastructures to deal with these phenomena is divided into resilience studies. To overcome these challenges, this thesis has attempted to detail some of these natural events.... 

Today, microfluidic experiments have found wide applications in medical sciences, engineering, and chemistry. Because of their small size, microfluidic devices help us to be able to use very little amount of sample for the experiments and also easily control and observe the under-experiment fluid. One of the most important applications of these devices is the separation of cancer cells in blood for counting their number and DNA genetic studies. In the current project we have tried to do the separation of cancer cells from other cells by designing an inertia microchannel. For this purpose, in the first step a geometry for the channel is designed with analyzing the induced forces on the cells....