Effects Of Rotation Parameter Research Articles

Thermal-Optical Mechanical Waves of the Excited Microelongated Semiconductor Layer in a Rotational Field

This work focuses on presenting a novel model describing a layer of an excited microelongated semiconductor material. During the photo-excitation processes, the model is investigated in a rotational field. The model introduced the microelongation scalar function, which describes the microelement processes according to the micropolar-thermoelasticity theory. The model studies the interaction case between optical-thermo-mechanical waves under the effect of rotation parameters when the microelongation parameters are taken into consideration according to the photo-thermoelasticity theory. The main governing equations have been taken in a dimensionless form during the electronic and thermoelastic deformation and they have been studied under the harmonic wave technique. The general solutions of the basic fields of isotropic, homogeneous, and linear microelongated semiconductor medium are obtained in two dimensions (2D). Many conditions are taken at the free surface of the medium to obtain the complete solutions. The physical parameters of silicon (Si) are used to illustrate the numerical simulation of the main fields. Several comparisons were performed and illustrated graphically under the influence of different parameters of relaxation time and rotation.

Gravitational Analysis of Rotating Charged Black‐Hole‐Like Solution in Einstein–Gauss–Bonnet Gravity

AbstractThis work analyzes the Einstein–Gauss–Bonnet gravity of charged black hole solutions through Newman–Janis approach. The Hawking temperature for corresponding black hole is also computed. The solution depends upon rotation parameter a, black hole mass, charge and horizon. Moreover, the graphical behavior of temperature via event horizon to analyze the stability of black hole under the effects of rotation parameter is discussed. The graphs are plotted in the presence/absence of rotation parameter and charge. Furthermore, the Hawking temperature under gravity effects is studied by using the semi‐classical method. It is also observed that the maximum temperature at non‐zero horizon depicts the BH remnant. Finally, the logarithmic corrected entropy for given black hole is computed and the logarithmic corrected entropy under effects of rotation and correction parameter are studied.

Numerical Investigations on Rotatry Micropolar Fluid in Hydromagnetics Permeated with Suspended Particles Saturating Porous Medium

This paper deals with the convection of micropolar fluids heated and soluted from below in the presence of suspended particles (fine dust) and uniform vertical rotation and uniform vertical magnetic field in a porous medium. Using the Boussinesq approximation, the linearized stability theory and normal mode analysis, the exact solutions are obtained for the case of two free boundaries. It is found that the presence of the suspended particles number density, the rotation parameter, stable solute, magnetic field intensity and medium permeability bring oscillatory modes which were non–existent in their absence. It is found that the presence of coupling between thermal and micropolar effects, rotation parameter, solute parameter and suspended particles may introduce overstability in the system. Graphs have been plotted by giving numerical values to the parameters accounting for rotation parameter , magnetic field solute parameter, the dynamic microrotation viscosity and coefficient of angular viscosity to depict the stability characteristics, for both the cases of stationary convection and overstability. It is found that Rayleigh number for the case of overstability and stationary convection increases with increase in rotation parameter, as well as with magnetic field intensity, solute parameter and decreases with increase in micropolar coefficients and medium permeability, for a fixed wave number, implying thereby the stabilizing effect of rotation parameter, magnetic field intensity ,solute parameter and destabilizing effect of micropolar coefficients and medium permeability on the thermosolutal convection of micropolar fluids.

Time dependence of advection-dominated accretion flow around a rotating compact object

ABSTRACT Time evolution of advection-dominated accretion flow (ADAF) around a rotating compact object is presented. The time-dependent equations of fluid including the Coriolis force along with the centrifugal and pressure gradient forces are derived. In this research, it is assumed that angular momentum transport is due to viscous turbulence and the α-prescription is used for the kinematic coefficient of viscosity. Moreover, the general relativistic effects are neglected. In order to solve the equations, we have used a self-similar solution. The solutions show that the behaviour of the physical quantities in a dynamical ADAF is different from that for a steady accretion flow. Our results indicate that the physical quantities are dependent of rotation parameter which is defined as the ratio of the intrinsic angular velocity of the central body to the angular velocity of disc. Also, the effect of rotation parameter on these quantities is different for co and counter-rotating flows. The solution shows that by increasing the rotation parameter a, inflow–outflow region approaches the central object for co-rotating flow and moves outwards for counter-rotating flow. We find that when flow is fully advection dominated (f → 1), the entire gas has positive Bernoulli function. Also, we suggest that the Bernoulli function becomes more positive when the effect of rotation on the structure of disc decreases.

Brinkman convection induced by purely internal heating in a rotating porous medium layer saturated by a nanofluid

The onset of Brinkman convection induced by purely internal heating in a rotating porous medium layer saturated by a nanofluid is investigated for rigid–rigid boundary surfaces with two sets of thermal boundary conditions namely, Case (i) – both boundaries isothermal – and Case (ii) – lower insulated and upper isothermal. The zero nanoparticle flux condition under the thermophoretic effects is taken at the boundaries. The model used for nanofluid combines the effects of Brownian motion and thermophoresis, while for porous medium Brinkman model is considered. The effect of rotation parameter, porosity parameter, Darcy number, Lewis number, nanoparticle Rayleigh number, modified diffusivity ratio and modified specific heat increment on the onset of convection is shown graphically and analyzed in detail. It is found that the Lewis number, the nanoparticle Rayleigh number and the modified diffusivity ratio have destabilizing effect on the onset of convection, while modified specific heat increment has no significant effect on the stability of the system. The rotation parameter, the porosity parameter and the Darcy number delay the onset of convection. The system is found to be more stable when both boundaries are isothermal.

MHD Free Convection Fluid Flow Through Parallel Plates with Hall Current in a Rotating System

An attempt has been made to study the influence of inclined magnetic field with hall current of a viscous incompressible electrically conducting free convection fluid flow through the parallel plates in a rotating system. The channel is rotating with uniform angular velocity about an axis normal to the plates. For numerical solution, the problems have been transferred into dimensionless form and then the explicit finite difference technique has been used. The stability conditions and convergence criteria of the explicit finite difference scheme are established for finding the restriction of the values of various parameters to get more accuracy. The effects of Rotation parameter, Hall parameter, Magnetic parameterand Angle of inclination on primary and secondary velocities have been shown in graphical representations. Finally the effects of these parameters have been analyzed by the figures of local shear stress and average current density at the moving plates of channel.

MHD Two-Fluid Flow and Heat Transfer between Two Inclined Parallel Plates in a Rotating System.

Two-phase magnetohydrodynamic convective flow of electrically conducting fluid through an inclined channel is studied under the action of a constant transverse magnetic field in a rotating system. The fluids in the two phases are steady, incompressible, laminar, immiscible, and electrically conducting, having different densities, viscosities, and thermal and electrical conductivities. The transport properties of both the fluids are assumed constant. The bounding infinite inclined parallel plates are maintained at different constant temperatures, making an angle ϕ with the horizontal. Approximate solutions for velocity and temperature distributions are obtained by using a straightforward regular perturbation technique. An in-depth study has been done on the effects of rotation parameter, Hartmann number, inclination angle, the ratio of electrical conductivities, and viscosities of two fluids on the flow. It is observed that the effect of increasing rotation is to decrease the primary velocity. Further it is noticed that as the rotation increases, the secondary velocity increases for smaller rotation, while for larger rotation it decreases. It is also found that the temperature distribution decreases as the rotation increases.

Hall Effects on Unsteady MHD Flow Between Two Rotating Disks with Non-Coincident Parallel Axes Embedded in a Porous Medium

Hall effects on an unsteady MHD flow of a viscous incompressible electrically conducting fluid between two rotating disks with non-coincident parallel axes embedded in a porous medium have been studied. The governing equations have been solved analytically using the Laplace transform technique. The effects of rotation parameter, Hall parameter, Hartmann number and Darcy number have been considered on the flow characteristics and illustrated by graphs. It is observed that the velocity components are significantly affected by Hall parameter and Darcy number. The velocity components increase near the lower disk whereas they decrease near the upper disk with an increase in either rotation parameter of disk or rotation parameter of axis. Further, the torque experienced by the disks increases with an increase in either Hartmann number or rotation parameter while it decreases with an increase in either Hall parameter or Darcy number.

Unsteady hydromagnetic couette flow in a rotating system

Unsteady hydromagnetic flow of an electrically conducting viscous incompressible fluid in a rotating system under the influence of a uniform transverse magnetic field is investigated when one of the plates is set into motion with the time dependent velocity U(t) in its own plane. Two cases of interest, namely, impulsive start as well as accelerated start of the moving plate are discussed. The asymptotic behaviour of the solution is also analysed for both small and large time to highlight the transient approach to the final steady state and effects of rotation parameter as well as Hartmann number. The shear stresses at the moving plate due to the primary and secondary flows are derived in both cases. It is found that the shear stress components due to the primary flow decrease, whereas that due to the secondary flow increase with the increase in rotation parameter.