Volume 1 Issue 2
Authors: Sobhan Mosayebidorcheh
Abstract: In this work, the electrohydrodynamic flow equation of a fluid in an ion drag configuration in a circular cylindrical conduit is considered. The differential equation of the problem is a highly nonlinear and singular boundary value problem (BVP). An analytical solution of the problem is presented using the differential transform method (DTM). In this method, the differential equation and related boundary conditions transformed into a recurrence set of equations and at the end, the coefficients of Taylor series are calculated based on the solution of this set of equations. DTM results are compared with the numerical solution of the problem and an excellent accuracy is observed. It showed that the proposed method overcame the nonlinearity and singularity of the problem without any need to restrict assumptions or linearization.
Keywords: Electrohydrodynamic Flow Equation; Singular Boundary Value Problem; Differential Transform Method; Taylor Series
Authors: Fathollah Ommi; Mohammadreza Azimi
Abstract: Nowadays, noise has turned into one of the most important among the environmental factors on which industry sets down a big part of its efforts and concerns. The quality of life of many people living under approach or departure flight paths can be affected by aircraft noise. These effects arise from the effect of noise on concentration or sleep and from feelings of anger, frustration and powerlessness to control the noise. Aircraft noise arises from both engines and the movement of turbulent air over the physical structure (airframe) of an aircraft. To date, noise reduction has focused mainly on reducing engine noise. Microinjection system, impacting the main jet, has shown the ability to suppress jet noise through velocity profile modifications. In this paper, the mechanism of microinjection system and the main applications, in both subsonic and supersonic flight condition, in turbofan engines are presented.
Keywords: Aircraft Noise Reduction; Aircraft Noise Effect; High Bypass Turbofan Engines; Engine Noise; Jet Noise; Jet Noise Reduction Technologies; Microjet
Authors: P. Ponnusamy; R . Selvamani
Abstract: The generalized thermo elastic waves in a rotating plate subjected to ramp type increase in boundary temperature is studied based on Lord-Shulman (LS) and Green-Lindsay (GL) generalized two dimensional theory of thermo elasticity. Two displacement potential functions are introduced to uncouple the equations of motion and heat conduction. The frequency equations are obtained by the traction free and ramp type thermal boundary conditions using Bessel function solutions. The numerical calculations are carried out for the material Zinc. The computed non-dimensional frequency and attenuation coefficient are plotted as dispersion curves.
Keywords: Wave Propagation in Plate; Vibration of Thermo Plate; Rotating Plate; Generalized Thermo Elastic Plate; Ramp Type Heating
Authors: A-H. I. Mourad; W. K. Ahmed
Abstract: Finite element analysis is used to investigate the effectiveness of Fiber Reinforced Polymers (FRP) bandage in rehabilitating misaligned welded pipes with outer circumferential surface crack. It is assumed that the pipes are subjected to an axial tensile stress. Linear Elastic Fracture Mechanics (LEFM) regime is adopted to estimate the stress intensity factor (SIF). ANSYS software is used in the study through 3D-axisymmetric finite element analysis. The results demonstrated that stiffening with FRP bandage has a great influence on the reduction of the stress intensity factor at the crack tip improving the fracture integrity of the misaligned welded pipes.
Keywords: Crack; FEA; LEFM; Misalignment; Pipes; SIF
Authors: Kamran Niazi; Masoud Goudarzi; Roghieh Irani Alamdari
Abstract: Converting vibrating energy of Magnetostrictive materials into electrical energy can be used in the manufacture of micro-generators, MEMS systems and sensors. Magnetostrictive materials behavior is nonlinear, but under the right conditions it can be assumed as linear behavior. In this paper, linear modeling of vibration energy using a single degree of freedom mass - spring – damper in natural frequency 250 Hz has been studied. The equivalent mass of the system is considered as a substrate on which a layer of Metglas2605SC metal is attached. In the present work, the effect of the random force is applied to the system support, as well as a comparison between the amounts of harvested energy while the support of the harmonic excitation has been studied. Finally, numerical results are presented for five different substrates.
Keywords: Energy Harvesting; Magnetostrictive Materials; Random Excitation; MEMS; Metglas2605SC
Authors: Jatinder Kumar; Vinod Kumar; Anish Kumar
Abstract: Wire electrical discharge machining (WEDM) is a non-traditional machining technique that is able to produce complicated and 3-D shapes through difficult machine metals without using high cost grinding or expensive formed tools. Wire electrical discharge machine should satisfy performance demands such as: high-speed cutting, resistant against wire rupture and accurate machining to improve the productivity and to achieve high quality in machining work pieces. Many factors have effect on the process of WEDM (cutting speed and work piece precision) including electrical parameters and electrode. But wire breakage frequency in the WEDM process decreases the productivity and quality of machined surface. This paper describes the effect of six input parameters i.e. Ton, Toff, Ip, SV, WF and WT on wire breakage frequency and the surface integrity of wear out wire during machining of pure titanium. An optimum range of input parameters has been selected for carrying out further research to develop the empirical models for WEDM of pure titanium.
Keywords: WEDM; Wire Breakage Frequency; Pure Titanium; Surface Topography