Browsing by Author "Miwadinou, C.H."

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    Effect of helical force
    (Elsevier, 2020-06) Hounsou, P.; Monwanou, A.V.; Miwadinou, C.H.; Orou, J.B. Chabi
    In this paper we studied the onset of instability in a horizontal layer of a rotating ferrofluid in the presence of the helical force. The analytical expression of the Rayleigh number of the system is determined as a function of the dimensionless numbers obtained. Then, the effect of each dimensionless parameter is studied. The helical force, the binary parameter ψ then the magnetic parameters M1, M3 and ψm accelerate the onset of stationary convection whereas the rotation and the magnetic parameter M2 delay it. Also all the magnetic parameters, the binary parameter and the rotation cause the convection rolls to shrink while only the helical force increases the size of these structures
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    Effects of Passive Hydrodynamics Force
    (Elsevier, 2018) Olabodé, D.L.; Miwadinou, C.H.; Monwanou, V.A.; Orou, Chabi J.B.
    This work studies the nonlinear dynamics and passive control of chemical oscillations governed by a forced modified Van der Pol-Duffing oscillator. We considered the dynamics of nonlinear chemical systems subjected to fluctuating hydrodynamic drag forces. The computation of fixed points of the nonlinear chemical system is made in detail by utilizing Cardan’s method. The harmonic balance method is used to find the amplitudes of the oscillatory states. The Floquet theory and the Whittaker method are utilized to analyze and analytically determine the stability boundaries of oscillations. The influences of system parameters in general and in particular the effect of the parameter K and the constraint parameter β which shows the difference between a nonlinear chemical dynamics order two differential equation and ordinary Van der Pol-Duffing equation are observed on the state of the second stability criterion. The effects of the control process on chaotic dynamics states are investigated through bifurcations structures, Lyapunov exponent, phase portraits and Poincar´e section. The results obtained by the analytical methods are validated and complemented by the results of numerical simulations.
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    Modeling and generation of electrodynamic modes
    (Springer-Verlag GmbH Germany, 2019-11-23) Koudafokê, N.G.; Miwadinou, C.H.; Monwanou, A.V.; Hinvi, A.L.; Orou, J.b. Chabi
    This work deals with the modeling of an active sensor consisting of a Josephson junction, a micro-beam immersed in a uniform magnetic field B, a dipole (r, L, C) and an auxiliary generator. In this work, an active sensor (independent of an external energy supply) capable of converting low temperature and/or a uniform magnetic field B into sinusoidal electrical voltage has been constructed. Being known as an excellent voltage-frequency converter, we have in a second time studied the influence of the Josephson junction on the oscillation frequency of the electrical and mechanical parts of the Micro Electro Mechanical System. An analytical study of the fixed points and their stability is done. On the other hand, the numerical studies have been done in order to show how the energy losses are compensated thanks to a simple rheostat of the auxiliary generator. The order of the influence of the Josephson junction on the oscillation frequencies and the different electrodynamic modes has been obtained.
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    Modeling and study of dynamics of micro-beam coupled to two Josephson junctions
    (IOP Publishing Ltd., 2019) Koudafokê, G.N.; Miwadinou, C.H.; Hinvi, A.L.; Monwanou, A.V.; Orou, Chabi J.B.
    In this work, we proposed to study the dynamics of a bi-recessed micro-beam coupled magnetically to two Josephson junctions. After building a model of MEMS (Micro Electro Mechanical Systems), the equations of their dynamics are determined. The fixed points of system are analytically checked and their stability is analyzed by using the Routh-Hurwitz criterion. For this purpose, a numerical study utilizing the bifurcation diagram, Lyapunov exponents, phase portraits and times hystories is made to analyze the different dynamic modes of micro-beam coupled to two Josephson junctions. The effect of Josephson junctions on the behavior of the micro-beam is seriously analyzed. It is obtained for each part of the MEMS the various dynamics influenced by certain parameters of the system.