Browsing by Subject "Nonlinear dynamical systems"

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    Adaptive control design for nonlinear systems via successive approximations
    (American Society of Mechanical Engineers, 2017) Babaei N.; Salamci M.U.; Karakurt A.H.
    The paper presents an approach to the Model Reference Adaptive Control (MRAC) design for nonlinear dynamical systems. A nonlinear reference system is considered such that its response is designed to be stable via Successive Approximation Approach (SAA). Having designed the stable reference model through the SAA, MRAC is then formulated for nonlinear plant dynamics with a new adaptation rule to guarantee the convergence of the nonlinear plant response to that of the response of the nonlinear reference model. The proposed design methodology is illustrated with examples for different case studies. Copyright © 2017 ASME.
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    Modeling and identification of combined effects of pulsating inlet temperature and use of hybrid nanofluid on the forced convection in phase change material filled cylinder
    (Taiwan Institute of Chemical Engineers, 2021) Selimefendigil F.; Öztop H.F.
    Effects of pulsating heat transfer fluid temperature and hybrid nano-additive inclusion in the base fluid are numerically studied for laminar forced convection through a phase change material embedded thermo-fluid system with finite element method. Effects of different values of Reynolds number (between 250 and 1000), amplitude (between 0 and 0.05) and frequency (Strouhal number between 0.01 and 0.5) of pulsating inlet temperature, nanoparticle volume fraction of hybrid particles (between 0 and 0.02) on the dynamic features of the system with performance characteristics are analyzed. It is observed that the phase change material onset temperature becomes oscillating with drastically reduction of full completion time as the Reynolds number and amplitude of pulsation are increased. The amount of reduction in the full phase transition is 63% when cases at Re=100 to Re=400 are compared. When lowest and highest amplitude configurations are compared, 62% reduction in the complete phase transition time is observed while the impact of frequency is marginal at higher frequencies. When the hybrid nanoparticles are introduced in the base fluid, transition time and dynamic features of onset temperatures are affected. Successful results that capture the dynamic behavior of the phase change embedded thermal system is achieved with a nonlinear dynamic system modeling approach. © 2021 Taiwan Institute of Chemical Engineers