Influence of the mass distribution on the stability behaviour of certain nonconservative systems of rods

1973 ◽  
Vol 24 (2) ◽  
pp. 255-269 ◽  
Author(s):  
Benno Buchser ◽  
Horst H. E. Leipholz
Keyword(s):  
Mass Distribution ◽  
Nonconservative Systems ◽  
Stability Behaviour ◽  
The Stability

Effects of finite-rate chemistry and detailed transport on the instability of jet diffusion flames

2014 ◽  
Vol 745 ◽  
pp. 647-681 ◽  
Author(s):  
Yee Chee See ◽  
Matthias Ihme
Keyword(s):  
Transport Properties ◽  
Diffusion Flames ◽  
Diffusive Transport ◽  
Mean Flow ◽  
Stability Behaviour ◽  
Jet Diffusion Flames ◽  
One Step ◽  
The Mean ◽  
Modelling Assumptions ◽  
The Stability

AbstractLocal linear stability analysis has been shown to provide valuable information about the response of jet diffusion flames to flow-field perturbations. However, this analysis commonly relies on several modelling assumptions about the mean flow prescription, the thermo-viscous-diffusive transport properties, and the complexity and representation of the chemical reaction mechanisms. In this work, the effects of these modelling assumptions on the stability behaviour of a jet diffusion flame are systematically investigated. A flamelet formulation is combined with linear stability theory to fully account for the effects of complex transport properties and the detailed reaction chemistry on the perturbation dynamics. The model is applied to a methane–air jet diffusion flame that was experimentally investigated by Füriet al.(Proc. Combust. Inst., vol. 29, 2002, pp. 1653–1661). Detailed simulations are performed to obtain mean flow quantities, about which the stability analysis is performed. Simulation results show that the growth rate of the inviscid instability mode is insensitive to the representation of the transport properties at low frequencies, and exhibits a stronger dependence on the mean flow representation. The effects of the complexity of the reaction chemistry on the stability behaviour are investigated in the context of an adiabatic jet flame configuration. Comparisons with a detailed chemical-kinetics model show that the use of a one-step chemistry representation in combination with a simplified viscous-diffusive transport model can affect the mean flow representation and heat release location, thereby modifying the instability behaviour. This is attributed to the shift in the flame structure predicted by the one-step chemistry model, and is further exacerbated by the representation of the transport properties. A pinch-point analysis is performed to investigate the stability behaviour; it is shown that the shear-layer instability is convectively unstable, while the outer buoyancy-driven instability mode transitions from absolutely to convectively unstable in the nozzle near field, and this transition point is dependent on the Froude number.

A Simplified Stability Criterion for Nonconservative Systems

1979 ◽  
Vol 46 (2) ◽  
pp. 423-426 ◽  
Author(s):  
I. Fawzy
Keyword(s):  
Dynamic Stability ◽  
Stability Criterion ◽  
Degrees Of Freedom ◽  
Necessary Condition ◽  
Matrix Methods ◽  
Nonconservative System ◽  
Nonconservative Systems ◽  
The Stability ◽  
Lyapunov’S Theorem ◽  
Sufficient And Necessary Condition

Dynamic stability of a general nonconservative system of n degrees of freedom is investigated. A sufficient and necessary condition for the stability of such a system is developed. It represents a simplified criterion based on the famous Lyapunov’s theorem which is proved afresh using λ-matrix methods only. When this criterion is adopted, it reduces the number of equations in Lyapunov’s method to less than half. A systematic procedure is then suggested for the stability investigation and its use is illustrated through a numerical example at the end of the paper.

Topological Hopf bifurcation in the plane

1983 ◽  
Vol 93 (1) ◽  
pp. 113-119
Author(s):  
Dieter Erle
Keyword(s):  
Hopf Bifurcation ◽  
Dynamical Systems ◽  
Asymptotic Stability ◽  
Stationary Point ◽  
Parameter Family ◽  
Stability Behaviour ◽  
Closed Orbits ◽  
The Stability ◽  
Image Position ◽  
Negative System

Classical bifurcation theorems for a 1 -parameter family of plane dynamical systemsassert the presence of closed orbits clustering at some distinguished parameter value (∈ = 0, say). Here, for any ∈, the origin is the only stationary point. The topological content of the mostly analytic hypotheses imposed is some change in the stability behaviour of the origin at ∈ = 0, roughly the passing of a kind of stability to a kind of instability. Topologically speaking, e.g. some of the conditions demanded are asymptotic stability of the origin for the negative system at ∈ > 0 and asymptotic stability of the origin for at ∈ < 0 (Hopf (8), Ruelle and Takens(11)) or ∈ = 0 (Chafee(2)).

Luminescent Polystyrene Composition Characteristics Stability Forecasting

2001 ◽  
Vol 708 ◽  
Author(s):  
Artem Yu. Borisenko ◽  
Vitalij G. Senchishin
Keyword(s):  
Injection Molding ◽  
Molecular Mass ◽  
Mass Distribution ◽  
Supramolecular Structure ◽  
Molecular Mass Distribution ◽  
Bulk Polymerization ◽  
Material Structure ◽  
Geometrical Size ◽  
The Stability ◽  
Plasticizer Concentration

ABSTRACTThe stability of properties of luminescent polystyrene compositions depending on their material structure has been studied. The samples obtained by the methods of bulk polymerization and injection molding were used for the experiment. The influence of molecular mass distribution, supramolecular structure, plasticizer concentration and geometrical size of samples on the stability of their properties in severe conditions of natural and radiation aging has been investigated.

scholarly journals Structure Analysis and Optimization for Compacting System of Asphalt Paver

2015 ◽  
Vol 9 (1) ◽  
pp. 86-91
Author(s):  
Sun Jian
Keyword(s):  
Mass Distribution ◽  
Asphalt Concrete ◽  
Impact Force ◽  
Inertial Force ◽  
Theoretical Method ◽  
Force Balance ◽  
Simplified Model ◽  
Inertia Force ◽  
The Stability

Compound motion of double-tamper mechanism causes an impact force on the frame of flatiron-box, which affects the quality of the load when the asphalt paver is running. Different from the previous simplified model, in this paper, the double-tamper mechanism with two parallel slider-cranks is considered. According to the analysis of the structure and principle of the mechanism, and considering the size and mass distribution of each component, the inertia force balance optimization for the double vibrating mechanism is calculated. According to the results of optimization, the vibration experiments were carried out on real screed. The experimental results show that, the harmful inertial force produced by the dual tamping mechanism has been significantly reduced, and the stability of vibration can be effectively improved when screed is paving. The research could provide reliable theoretical method and basis for design, manufacturing and use of asphalt concrete paver.

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