Potential flow over Rotating cylinder is usually solved by the singularity method. However, in this paper a mathematical solution is presented for this problem by direct solution of the Laplace' s equation. Flow over the cylinder was considered non-viscous. Neumann and Dirichlet boundary conditions were used on the solid surfaces and in the infinity, respectively. Because of non-viscous flow, the Laplace equation is the governing equation of the flow field. The entire flow field was divided into two parts including tree stream over a stationary cylinder and flow over a Rotating cylinder with no free stream. Because of linearity of the governing equation, solutions of these flows were superposed to obtain velocity potential function from which velocity and pressure distribution was obtained. Pressure forces acting on the cylinder were obtained by integrating pressure distribution over the cylinder surface that was exactly the same as the results of the singularity method. Present work achieved the famous Kutta-Joukowski theorem in the aerodynamics and fluid mechanics. In addition, the proposed analytical model was validated by numerical solution.

Heat transfer analysis in channels and enclosures has significant attention nowadays. In the present work, fluid flow and heat transfer of a vertical channel consisting of a Rotating cylinder utilizing nanofluid have been studied, numerically. Uniform magnetic field has been applied to the fluid field. Different cylinder rotation directions, Hartmann number and rotational velocity of cylinder configurations have been considered. The results indicate that by increasing the Hartmann number, for low values of non-dimensional angular velocity the average Nusselt number increases. In addition, in higher Hartmann numbers, the average Nusselt number does not change remarkably with non-dimensional angular velocity. Furthermore, studying lift and drag coefficients demonstrate that in a constant Hartmann number, the highest drag coefficient takes place in maximum cylinder angular velocity. Additionally, almost uniform distribution of drag coefficient can be seen in higher Hartmann numbers. The numerical results have been compared with the previously reported results. This comparison illustrates excellent agreement between them.

An elastoplastic Rotating cylinder with a rigid inclusion and fixed ends is investigated. The analysis is based on infinitesimal strain theory, Schmidt-Ishlinskii yield criterion, and its associated flow rule and perfectly plastic material behavior. Both loading and unloading stages are studied. The closed-formed solutions for all stages of deformation including secondary plastic flow are obtained. The results are illustrated by the distributions of the stresses and plastic strains in a cylinder Rotating at different speeds.

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%

Rotating cylinders have wide applications in different areas, especially the aerodynamic area. However, the acoustic behaviors of these components have not been widely studied. The generating noise from a spinning cylinder is mainly due to the detached vortices from the leeward of the body. In this study, the large eddy simulation technique is used to simulate the flow field over a three-dimensional cylinder. In the following, the Ffowcs Williams and Hawkings equation is used to estimate the noise at the specified locations using the oscillating pressure components on the cylinder wall. The acoustic behavior of both stationary and Rotating cylinders are studied. Results show that the acoustic behaviors of cylinders Rotating with smaller frequencies (up to f=16f0, where f0 is the dominant detaching frequency of vortices on a stationary cylinder) are nearly the same. However, at higher rotational frequencies (24f0) where vortices are omitted, OASPL of the generated noise is reduced considerably (about 20 dB at different angles with constant radial positions, r=26D, at mid-span plane). On the other hand, when the rotational frequency is increased over this limit, the pressure oscillation on the wall becomes significant and the OASPL approaches higher values.

Time-dependent creep analysis is crucial for the performance and reliability of piezoactuators used for high-precision positioning and load-bearing applications. In this study history of stresses, deformations and electric potential of hollow Rotating cylinders made of functionally graded piezoelectric material (FGPM), e.g., PZT-7A have been investigated using Mendelson’s method of successive elastic solution. Loading is composed of an internal pressure, a distributed temperature field, an inertia body force and a constant electric potential difference between the inner and outer surfaces of the FGPM cylinder. All the mechanical, thermal and piezoelectric properties are assumed to be the same power functions of the radial graded direction. Using equations of equilibrium, strain displacement, stress-strain relation and the electric potential equation a differential equation containing creep strains for displacement is derived. A semi-analytical method in conjunction with the method of successive approximation has therefore been proposed for this analysis. It has been found that a major redistribution for electric potential take place throughout the thickness. Electric potentials are increasing with time in the same direction as the compressive radial stress histories. That is the electric potential histories are induced by the compressive radial stress histories during creep deformation of the FGPM cylinder.

Two-dimensional numerical simulations have been carried out on flow past two inline circular cylinders with Rotating downstream cylinder. Computations are performed for fixed Reynolds number equal to 150 such that the resulting flow field remains laminar and two-dimensional. The inter-cylinder spacing has been chosen equal to 5d ('d' being diameter of cylinder) such that the wake flow is predominantly unsteady. Rotational speed of the downstream cylinder has been varied to investigate its effect on transition in characteristics of temporal wake. This has been achieved by performing Hilbert-Huang transformation (HHT) on time series signals of drag and lift coefficients for the Rotating cylinder. Unsteady periodic, unsteady non-periodic and steady transitions in flow behavior have been observed with an increase of rotational speed. Results are presented in the form of vorticity contours, Hilbert spectra and marginal spectra. Degree of stationarity of the signals as measure of nonlinearity has also been quantified. Comparisons are drawn against results from Fourier analysis and it has been shown that HHT is better suited to capture inter-wave and intra-wave modulations indicating nonlinear interactions in the wake.

In this work, we attempted to simulate UF6 gas flow in the rarefied and continuum areas of the Rotating cylinder using CFD, DSMC, and hybrid one-way and two-way CFD-DSMC methods. In the hybrid two-way CFD-DSMC method, the effect of two rarefied and continuum areas on each other is considered. The results were verified by the DSMC method. The results presented the two-way CFD-DSMC method was useful for three goals. The first purpose was to simulate the flow in the rarefied area using the DSMC method, which was more valid than the CFD method. The second goal was to reduce the computational time of the simulation of the continuum area using the CFD method. The third goal was to investigate the effect of the rarefied solution on the continuum solution. Comparing the results with the DSMC method, it was found that the two-way CFD-DSMC method causes a difference of only 2% for the separation power, while the computational cost is reduced by 60%.