abstract: since the field of micro electromechanical systems (mems) continues to grow, the flow in micro devices have become an area that receives a significant attention. the microscopic flows are usually characterized by the knudsen number (kn). when the characteristic size of the particle decreases down to a value comparable to the mean free path of the molecules, the continuum assumption fa...

in this study, the effect of the levels of hydrogen addition to methane-air premixed flame in a micro-stepped reactor has been studied numerically. in addition, the effects of mixture velocity and walls’ thermal conductivity (kw) on the flame’s location, temperature, and species distribution in a micro reactor were calculated using a 2d numerical laminar steady code. the results showed that an ...

Abstract We propose criteria of tracking vortex surfaces in complex flows based on the vortex-surface field (VSF). The characterize accuracy and Lagrangian performance numerical VSF solution, determine time period when surface is satisfactory. Moreover, we develop a turbulent-like flow combining large-scale coherent structures Taylor–Green small-scale turbulent homogeneous isotropic turbulence ...

in many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. for any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. the failure will happen in the equipment, when this frequency is close to one...

We study the flux tube junctions in the limit of large magnetic flux. In this limit the flux tube becomes a wall vortex which is a wall of negligible thickness (compared to the radius of the tube) compactified on a cylinder and stabilized by the flux inside. This wall surface can also assume different shapes that correspond to soliton junctions. We can have a flux tube that ends on a wall, a fl...

In this study, a functional vest which can be worked by manuel without any starting system was designed and a prototype was produced for peoples cooling requirement. This system was made of a vortex tube, knee pad, linear motion mechanism with 3 members and vest. While walking, depending on knee’s movement, a piston at linear motion mechanism was moved front and backward. This front and back mo...

Formation of vortex rings at the exit of a shock tube is studied theoretically. A model for predicting the maximum circulation that a vortex ring can attain at the exit of a shock tube is offered. To achieve maximum circulation the initial conditions and the design of the driver and driven sections must be such that the generated shock wave reaches the shock tube exit at least 4Dn/^2 time units...