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3D simulation of incompressible flow around a rotating turbulator: Effect of rotational and direction speed

Zoubai Elhadi, Laidoudi Houssem, Tlanbout Ismail, Makinde Oluwole Daniel

Archives of Thermodynamics

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2023

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Vol. 44, no 2

139--157

EN

This paper presents new results for the dynamic behaviour of fluid around a rotating turbulator in a channel. The turbulator has a propeller form which is placed inside a flat channel. The research was carried out using 3D numerical simulation. The rationale of the experiment was as follows: we put a propeller-turbulator inside a flat channel, and then we insert a water flow inside the channel. The turbulator rotates at a constant and uniform speed. The main points studied here are the effect of the presence of turbulator and its rotational direction on the flow behaviour behind the turbulator. The results showed that the behaviour of flow behind the turbulator is mainly related to the direction of turbulator rotating. Also, the studied parameters affect coefficients of drag force and power number. For example, when the turbulator rotates in the positive direction, the drag coefficient decreases in terms of rotational speed of the turbulator, while the drag coefficient increases in terms of rotational speed when the turbulator rotates in the negative direction.

2

Thermoelastic stresses in functionally graded rotating annular disks with variable thickness

Allam M. N. M., Tantawy R., Zenkour A. M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

1029--1041

EN

This article presents semi-analytical solutions for stress distributions in exponentially and functionally graded rotating annular disks with arbitrary thickness variations. The disk is under pressure on its boundary surfaces and exposed to temperature distribution varying linearly across thickness. Material properties are supposed to be graded in the radial direction of the disk and obeying to two different forms of distribution of volume fraction of constituents. Different conditions at boundaries for stresses and displacement are discussed. Accurate and efficient solutions for displacement and stresses in rotating annular disks are determined using infinitesimal theory. Numerical results are carried out and discussed for different cases. It can be deduced that the gradient of material properties and thickness variation as well as the change of temperature sources have a specific effect in modern applications.

3

Unsteady MHD flow due to non-coaxial rotations of a porous disk and a fluid at infinity subjected to a periodic suction

Guria M.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 3

623--633

EN

The unsteady flow of a viscous incompressible electrically conducting fluid due to non-coaxial rotations of a porous disk subjected to a periodic suction and the fluid at infinity in the presence of applied transverse magnetic field has been studied. The fluid at infinity passes through a fixed point. The velocity field, shear stresses are obtained in a closed form.

4

Unsteady flow through a porous medium due to noncoaxial rotations of a porous disk and a fluid at infinity subjected to a periodic suction

Guria M.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 2

401--411

EN

The unsteady flow of a viscous incompressible fluid due to non-coaxial rotations of a porous disk and a fluid at infinity subjected to a periodic suction through a porous medium has been studied. The velocity field, shear stresses are obtained in closed form. The variations of primary and secondary velocities for different values of non dimensional parameters are depicted in figures.

5

Oscillatory MHD convective flow of second order fluid through porous medium in a vertical rotating channel in slip-flow regime with heat radiation

Garg B. P., Singh K. D., Bansal A. K.

International Journal of Applied Mechanics and Engineering

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2015

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Vol. 20, no. 1

33--52

EN

An analysis of an oscillatory magnetohydrodynamic (MHD) convective flow of a second order (viscoelastic), incompressible, and electrically conducting fluid through a porous medium bounded by two infinite vertical parallel porous plates is presented. The two porous plates with slip-flow condition and the no-slip condition are subjected respectively to a constant injection and suction velocity. The pressure gradient in the channel varies periodically with time. A magnetic field of uniform strength is applied in the direction perpendicular to the planes of the plates. The induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The temperature of the plate with no-slip condition is non-uniform and oscillates periodically with time and the temperature difference of the two plates is assumed high enough to induce heat radiation. The entire system rotates in unison about the axis perpendicular to the planes of the plates. Adopting complex variable notations, a closed form solution of the problem is obtained. The analytical results are evaluated numerically and then presented graphically to discuss in detail the effects of different parameters of the problem. The velocity, temperature and the skin-friction in terms of its amplitude and phase angle have been shown graphically to observe the effects of the viscoelastic parameter γ, rotation parameter Ω, suction parameter […], Grashof number Gr, Hartmann number M, the pressure A, Prandtl number Pr, radiation parameter N and the frequency of oscillation […].

6

Dynamika stanów przejściowych mas wirujących

Buśkiewicz J.

Zeszyty Naukowe Politechniki Poznańskiej. Mechanika

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1999

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Nr 46

5-16

PL

Przedmiotem artykułu jest analiza warunków zachodzących podczas rozruchu niewyważonej tarczy kołowej osadzonej na sprężystym pionowym wale. Zakłada się, że środek masy tarczy zbacza o pewną małą odległość od jej środka geometrycznego, czyli od osi obrotu tarczy. Podano założenia, przy których następnie wyprowadzono równania ruchu oraz sformułowano warunki początkowe. Zbadano zachowanie się wału w trakcie przechodzenia przez zakres rezonansu. Przedstawiono rozwiązania numerycznie równań ruchu.

EN

This paper is aimed at analysis the conditions occurring at starting an unbalanced circular disk attached to an elastic, vertical shaft. It is assumed that the centre of mass of the disk deviates from its geometrical midpoint, i.e. from the axes of rotation of the disk, by a small distance. Appropriate assumptions are provided, serving for purposes of formulating the equations of motion and initial conditions. Behaviour of the shaft during its transition through resonance range was studied. The numerical solutions were presented and discussed for several cases.

7

Stability of a shaft rotating with fluctuating angular velocity

Tylikowski A.

Mechanics and Mechanical Engineering

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1999

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Vol. 3, nr 2

93--102

EN

In this paper the technique of the dynamic stability analysis proposed for the conven¬tional laminated structures is extended to the structures rotating with the time-dependent angular velocity. The rotating angle-ply symmetrically laminated circular cylindrical shell is treated as a beam-like structure. The shaft is subjected to a constant torque. The ve¬locity stochastic component is assumed in the form of the wide - band Gaussian processes modelled as a Wiener process. The fluctuating component of angular velocity implies a stochastic parametric excitation of shaft motion. The structure buckles dynamically when the axial parametric excitation becomes so large that the structure does not os¬cillate about the unperturbed state, and a new increasing mode of oscillations occurs. The uniform stochastic stability criteria involving a damping coefficient, a rotation speed and geometrical and material parameters are derived using Liapunov's direct method. Formulas determining dynamic stability regions are written explicitly.