The possibility of suppressing laminar vortex shedding after a Rectangular cylinder with a pair of rotating controllers has been investigated for Re=150. Drag and lift coefficients of the Rectangular cylinder have been measured at different positions of the controller system. Numerical results show that the controller system suppresses the vortex shedding completely when installing at some suitable positions. It was found that the controller system affects the vorticity intensity in the separation bubbles at these suitable positions. The controller system may completely eliminate the separation bubble or may make them remain in attached to the cylinder. Besides, the effectiveness sensitivity of the controller system to its rotation rate and Reynolds number was analyzed when installing at the edge of the cylinder boundary layer where its position is denoted by (r/a=2, q=40o). These analyses show that the controller system can still suppress the laminar vortex shedding completely when the rotation rate of the controller system and Reynolds number of the incoming flow change by less than 50%

In this work, the characteristics of the near wake of a Rectangular cylinder was investigated in a two-dimensional analysis, using hot-wire anemometer. The time-averaged and the fluctuating components of velocity were measured for the cylinder having various width-to-height ratios. The measurements were carried out in a low-speed wind tunnel. The results show that the wake turbulence intensity decreases, as the width-to-height ratio of the cylinder increases. Also, the characteristics of the flow field in different stream wise locations were evaluated. The spectral analysis of the signals was also carried out for two different Reynolds numbers. This showed that the strouhal number remains nearly constant in high Reynolds numbers. The results of our experiments were in close agreements with the most widely accepted results in the literature.

A numerical investigation has been carried out for mixed convection flow in a Rectangular ventilated cavity with a heat conducting solid circular cylinder at the center. Forced convection flow conditions were imposed by providing an inlet at the bottom of the left wall and an outlet vent at the top to the other sidewall. In this paper, the effect of cavity aspect ratio as well as the mixed convection parameter on the flow and heat transfer characteristics were analyzed. Finite element method was used to carry out the investigation. Computations were done for mixed convective flow with the Richardson number Ri ranging from 0.0 to 5.0, cavity aspect ratio from 0.5 to 2.0 and Reynolds number, Re of 100.The basic nature of the resulting interaction between the forced external air stream and the buoyancydriven flow by the heat source was explained by the patterns of the streamlines and isotherms. The computational results indicated that the flow and thermal fields as well as average Nusselt number at the hot wall, average temperature of the fluid and the temperature at the cylinder center strongly depended on the cavity aspect ratio and mixed convection parameter Ri.

In this paper, the flow field around a two-dimensional Rectangular cylinder was numerically simulated and the effects of the flow suction on the separation bubble were investigated. The purpose was to estimate the effect of suction on the dimensions of the separation bubble. The flow field was assumed incompressible, turbulent, and two-dimensional. Gambit software was used for grid generation and FLUENT for numerical simulation. The problem was analyzed in two states: with and without suction, and the effect of suction on the separation bubble was investigated. According to the results, it can be said that the suction length of the separation bubble is smaller, so that in several different cases this length is reduced by about 50%.

Fluid flow around and heat transfer from a Rectangular flat plane with constant uniform heat flux in laminar pulsating flows is studied, and compared with our experimental data. Quantitatively accurate, second-order schemes for time, space, momentum and energy are employed, and fine meshes are adopted. The numerical results agree well with experimental data. Results found that the heat transfer enhancement is caused by the relative low temperature gradient in the thermal boundary layer, and by the lower surface temperature in pulsating flows. In addition, the heat transfer resistance is much lower during reverse flow period than that during forward flow period. The flow reversal period is about 180 degree behind the pulsating pressure waves. Besides, spectrum results of the simulated averaged surface temperature showed that the temperature fluctuates in multiple-peaked modes when the amplitude of the imposed pulsations is larger, whereas the temperature fluctuates in a single-peaked mode when the amplitude of the imposed pulsation is small.

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating Rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the numerical method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.

Intersecting cylindrical shells are frequently encountered in various types of engineering structures. Despite their common occurrence, reliable and accurate analytical methods have not been generally available, and consequently accurate design information for such configurations has also been generally lacking. To contribute to the understanding of the problem, a finite element analysis is carried out for two normally intersecting cylindrical shells. Two types of loading have been applied to the structure. Results of stresses are provided, of both the outside and the inside, for the two shells. The overall agreement between the finite element predictions and experimental results is a very good one. It has been shown that by using the finite element method together with a "mesh generation" technique, both computational efficiency and minimum user time can be retained.      

Packing Rectangular shapes into a Rectangular space is one of the most important discussions on Cutting & Packing problems (C&P); such as: cutting problem, bin-packing problem and distributors pallet loading problem, etc. Assume a set of Rectangular pieces with specific lengths, widths and utility values. Also assume a Rectangular packing space with specific width and length. The objective function is, to pack the pieces into the space in Order to get the maximum sum of utility value of the packed pieces. To generate the related packing pattern this paper proposes a new formulation metl10dbased on the column generation, approach. In this method one each cycle of the algorithm; a one-dimensional pattern is generated based on the shadow prices 'Of the Simplex method. The set of generated one-dimensional patterns are used: to construct the two-dimensional packing pattern. Also, the proposed model and the present models in the.state-of-1beart have been compared.

Two dimensional flow past circular cylinder confined by walls with local waviness near the cylinder has been studied. The aim of the present study is to identify the ability of the waviness to control vortex shedding, for which two different waviness configurations such as in-phase configurations (IPC) and out-phase configurations (OPC) are considered. Further, the effect of location of the local waviness with respect to the cylinder has also been studied. Air is the working fluid and the flow is assumed to be laminar and incompressible at Re=200. The finite volume based CFD solver Ansys Fluent (Version 15. 0) is used for the computations. Flow characteristics such as drag, lift and Strouhal number are computed. Interesting shedding characteristics and drag reduction are observed due to the presence of local waviness. However, the significant factor is the location of waviness in the confining walls that leads to complete suppression of shedding. Among various locations and configurations of waviness studied, waviness in downstream with OPC3 suppresses the vortex shedding completely with reduced drag.

We first prove that there always exists a maximal Rectangularly dualizable graph for a given Rectangularly dualizable graph and present an algorithm for its construction. Further, we show that a maximal Rectangularly dualizable graph can always be transformed to an edge-irreducible Rectangularly dualizable graph and present an algorithm that transforms a maximal Rectangularly dualizable graph to an edge-irreducible Rectangularly dualizable graph.