Dynamics of a Supported Cylinder in Axial Flow

2011 ◽  
Vol 99-100 ◽  
pp. 1059-1062
Author(s):  
Ji Duo Jin ◽  
Ning Li ◽  
Zhao Hong Qin
Keyword(s):  
Nonlinear Dynamics ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Nonlinear Model ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Viscous Force ◽  
Friction Drag ◽  
Flutter Instability ◽  
Nonlinear Force

The nonlinear dynamics are studied for a supported cylinder subjected to axial flow. A nonlinear model is presented for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are the quadratic viscous force and the structural nonlinear force induced by the lateral motions of the cylinder. Using two-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain the flutter instability found in the experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the new equilibrium (the buckled configuration) becomes unstable at higher flow leading to post-divergence flutter. The effect of the friction drag coefficients on the behavior of the system is investigated.

Nonlinear Dynamics of a Slender Flexible Cylinder in Axial Flow

2011 ◽  
Vol 130-134 ◽  
pp. 761-765
Author(s):  
Ji Duo Jin ◽  
N. Li ◽  
Zhao Hong Qin
Keyword(s):  
Nonlinear Dynamics ◽  
Flow Velocity ◽  
Nonlinear Model ◽  
Dynamic Instability ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Viscous Force ◽  
Flexible Cylinder ◽  
Flutter Instability ◽  
The Stability

The stability and nonlinear dynamics are studied for a slender flexible cylinder subjected to axial flow. A nonlinear model is presented, based on the corresponding linear equation of motion, for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are the quadratic viscous force and the additional axial force induced by the lateral motions of the cylinder. Using two-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain, with this relatively simple nonlinear model, the flutter instability found in experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the buckled configuration becomes unstable at higher flow leading to post-divergence flutter. As the flow velocity increases further, the system is restabilized in the buckled configuration prior to another dynamic instability at higher flow.

Stability of a Supported Cylinder in Axial Flow

2011 ◽  
Vol 117-119 ◽  
pp. 295-298
Author(s):  
Ji Duo Jin ◽  
Ning Li
Keyword(s):  
Numerical Analysis ◽  
Numerical Method ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Analytical Form ◽  
Viscous Force ◽  
Nonlinear Force ◽  
The Stability ◽  
Parameter Values ◽  
Zero Equilibrium

The stability of a supported cylinder subjected to axial flow is studied numerically. The dynamics of the cylinder is investigated with the numerical method applying the new nonlinear model in witch the nonlinear terms considered are the quadratic viscous force and the structural nonlinear force induced by the lateral motions of the cylinder. Using three-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder. Some integration terms that appear in the discretization of the equation and can not be expressed in an analytical form are calculated using a numerical method. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence and at a higher velocity the flutter around the zero equilibrium may occur. There is some region in witch three different motions (configurations) can take place at the same parameter values.

Nonlinear Dynamics of Supported Cylinder Subjected to Axial Flow

2011 ◽  
Vol 243-249 ◽  
pp. 4712-4717
Author(s):  
Ji Duo Jin ◽  
Zhao Hong Qin
Keyword(s):  
Nonlinear Dynamics ◽  
Flow Velocity ◽  
Nonlinear Model ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Equation Of Motion ◽  
Flexible Cylinder ◽  
Chaotic Motions ◽  
Flutter Instability ◽  
The Stability

In this paper, the stability and nonlinear dynamics are studied for a slender flexible cylinder subjected to axial flow. A nonlinear model is presented, based on the corresponding linear equation of motion, for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are only the additional axial force induced by the lateral motions of the cylinder. Using six-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain, with this relatively simple nonlinear model, the flutter instability found in experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the new equilibrium (the buckled configuration) becomes unstable at higher flow leading to post-divergence flutter. As the flow velocity increases further, the quasiperiodic motion around the buckled position occurs, and this evolves into chaotic motions at higher flow.

scholarly journals Nonlinear dynamics of pipeline with liquid in a vicinity of critical flow velocities

2008 ◽  
Vol 30 (4) ◽  
Author(s):  
O. Limarchenko ◽  
Yu. Vasilevskiy
Keyword(s):  
Nonlinear Dynamics ◽  
Variational Methods ◽  
Critical Velocity ◽  
Nonlinear Model ◽  
Discrete Model ◽  
High Speed ◽  
Dynamical Behavior ◽  
Critical Flow ◽  
Liquid Motion ◽  
Straight Line

We developed the nonlinear model of pipeline dynamics with high-speed liquid motion. On the basis of the variational methods we constructed the nonlinear discrete model and numerical algorithm for investigation of problems of dynamics and dynamical stability of pipeline. We considered examples of dynamical behavior of the system for different velocities of liquid flowing, including the case of critical velocity of flow, when loss of straight line stability of pipeline is possible.

Nonlinear Dynamics and Application of the Four Dimensional Autonomous Hyper-Chaotic System

2014 ◽  
Author(s):  
Ge Kai ◽  
Wei Zhang
Keyword(s):  
Nonlinear Dynamics ◽  
Numerical Simulation ◽  
Differential Equations ◽  
Chaotic System ◽  
Dynamical Behavior ◽  
Three Dimensional ◽  
Phase Portraits ◽  
State Variables ◽  
Chaotic Motions ◽  
Finance System

In this paper, we establish a dynamic model of the hyper-chaotic finance system which is composed of four sub-blocks: production, money, stock and labor force. We use four first-order differential equations to describe the time variations of four state variables which are the interest rate, the investment demand, the price exponent and the average profit margin. The hyper-chaotic finance system has simplified the system of four dimensional autonomous differential equations. According to four dimensional differential equations, numerical simulations are carried out to find the nonlinear dynamics characteristic of the system. From numerical simulation, we obtain the three dimensional phase portraits that show the nonlinear response of the hyper-chaotic finance system. From the results of numerical simulation, it is found that there exist periodic motions and chaotic motions under specific conditions. In addition, it is observed that the parameter of the saving has significant influence on the nonlinear dynamical behavior of the four dimensional autonomous hyper-chaotic system.

Optimal Synchronization of a Memristive Chaotic Circuit

2016 ◽  
Vol 26 (06) ◽  
pp. 1650093 ◽  
Author(s):  
Michaux Kountchou ◽  
Patrick Louodop ◽  
Samuel Bowong ◽  
Hilaire Fotsin ◽  
Jurgen Kurths
Keyword(s):  
Numerical Simulations ◽  
Chaos Synchronization ◽  
Chaotic Systems ◽  
Analog Circuit ◽  
Electronic Circuit ◽  
Dynamical Behavior ◽  
Circuit Implementation ◽  
Chaotic Circuit ◽  
Dynamical Properties ◽  
Analog Circuit Implementation

This paper deals with the problem of optimal synchronization of two identical memristive chaotic systems. We first study some basic dynamical properties and behaviors of a memristor oscillator with a simple topology. An electronic circuit (analog simulator) is proposed to investigate the dynamical behavior of the system. An optimal synchronization strategy based on the controllability functions method with a mixed cost functional is investigated. A finite horizon is explicitly computed such that the chaos synchronization is achieved at an established time. Numerical simulations are presented to verify the effectiveness of the proposed synchronization strategy. Pspice analog circuit implementation of the complete master-slave-controller systems is also presented to show the feasibility of the proposed scheme.

An explicit plethora of soliton solutions for a new microtubules transmission lines model: A fractional comparison

2021 ◽  
Author(s):  
Nauman Raza ◽  
Ziyad A. Alhussain
Keyword(s):  
Nonlinear Dynamics ◽  
Transmission Lines ◽  
Fractional Derivatives ◽  
Intracellular Transport ◽  
Dynamical Behavior ◽  
Soliton Solutions ◽  
Algebraic Method ◽  
Governing System ◽  
Parameter Values ◽  
Fractional Parameter

This paper introduces a new fractional electrical microtubules transmission lines model in the sense of Atangana–Baleanu and beta derivatives to comprehend nonlinear dynamics of the governing system. This structure possesses one of the most important parts in cellular process biology and fractional parameter incorporates the memory effects in microtubules. Also, microtubules are extremely beneficial in cell motility, signaling and intracellular transport. The new extended direct algebraic method is a compelling and persuasive integrating scheme to extract soliton solutions. The retrieved solutions include dark, bright and singular solitons. This model executes a prominent part in exhibiting the wave transmission in nonlinear systems. The novelty and advantage of the proposed method are portrayed by applying it to this model and its dynamical behavior is depicted by 3D and 2D plots. A comparative study of two fractional derivatives at distinct fractional parameter values and graphics of sensitivity analysis is also carried out in this paper.

Numerical Analysis of Non-Radial Blading in a Low Speed and Low Pressure Turbine for Electric Turbocompounding Applications

2021 ◽  
Author(s):  
Eva Alvarez-Regueiro ◽  
Esperanza Barrera-Medrano ◽  
Ricardo Martinez-Botas ◽  
Srithar Rajoo
Keyword(s):  
Numerical Analysis ◽  
Numerical Simulations ◽  
Thermal Stresses ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Blade Angle ◽  
Low Speed

Abstract This paper presents a CFD-based numerical analysis on the potential benefits of non-radial blading turbine for low speed-low pressure applications. Electric turbocompounding is a waste heat recovery technology consisting of a turbine coupled to a generator that transforms the energy left over in the engine exhaust gases, which is typically found at low pressure, into electricity. Turbines designed to operate at low specific speed are ideal for these applications since the peak efficiency occurs at lower pressure ratios than conventional high speed turbines. The baseline design consisted of a vaneless radial fibre turbine, operating at 1.2 pressure ratio and 28,000rpm. Experimental low temperature tests were carried out with the baseline radial blading turbine at nominal, lower and higher pressure ratio operating conditions to validate numerical simulations. The baseline turbine incidence angle effect was studied and positive inlet blade angle impact was assessed in the current paper. Four different turbine rotor designs of 20, 30, 40 and 50° of positive inlet blade angle are presented, with the aim to reduce the losses associated to positive incidence, specially at midspan. The volute domain was included in all CFD calculations to take into account the volute-rotor interactions. The results obtained from numerical simulations of the modified designs were compared with those from the baseline turbine rotor at design and off-design conditions. Total-to-static efficiency improved in all the non-radial blading designs at all operating points considered, by maximum of 1.5% at design conditions and 5% at off-design conditions, particularly at low pressure ratio. As non-radial fibre blading may be susceptible to high centrifugal and thermal stresses, a structural analysis was performed to assess the feasibility of each design. Most of non-radial blading designs showed acceptable levels of stress and deformation.

A nonlinear model for a free-clamped cylinder subjected to confined axial flow

2018 ◽  
Vol 80 ◽  
pp. 390-404 ◽  
Author(s):  
A.R. Abdelbaki ◽  
M.P. Païdoussis ◽  
A.K. Misra
Keyword(s):  
Nonlinear Model ◽  
Axial Flow

The Effect of the Thickness and Angle of the Inlet and Outlet Guide Vane on the Performance of Axial-Flow Pump

2016 ◽  
Author(s):  
Sang-Won Kim ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Numerical Study ◽  
Guide Vane ◽  
Axial Flow ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Pump Performance ◽  
Blade Thickness ◽  
Axial Flow Pump ◽  
Flow Pump

An axial-flow pump has a relatively high discharge flow rate and specific speed at a relatively low head and it consists of an inlet guide vane, impeller, and outlet guide vane. The interaction of the flow through the inlet guide vane, impeller, and outlet guide vane of the axial-flow pump has a significant effect on its performance. Of those components, the guide vanes especially can improve the head and efficiency of the pump by transforming the kinetic energy of the rotating flow, which has a tangential velocity component, into pressure energy. Accordingly, the geometric configurations of the guide vanes such as blade thickness and angle are crucial design factors for determining the performance of the axial-flow pump. As the reliability of Computational Fluid Dynamics (CFD) has been elevated together with the advance in computer technology, numerical analysis using CFD has recently become an alternative to empirical experiment due to its high reliability to measure the flow field. Thus, in this study, 1,200mm axial-flow pump having an inlet guide vane and impeller with 4 blades and an outlet guide vane with 6 blades was numerically investigated. Numerical study was conducted using the commercial CFD code, ANSYS CFX ver. 16.1, in order to elucidate the effect of the thickness and angle of the guide vanes on the performance of 1,200mm axial-flow pump. The stage condition, which averages the fluxes between interfaces and is accordingly appropriate for the evaluation of pump performance, was adopted as the interface condition between the guide vanes and the impeller. The rotational periodicity condition was used in order to enable a simplified geometry to be used since the guide vanes feature multiple identical regions. The shear stress transport (SST) k-ω model, predicting the turbulence within the flow in good agreement, was also employed in the CFD calculation. With regard to the numerical simulation results, the characteristics of the pressure distribution were discussed in detail. The pump performance, which will determine how well an axial-flow pump will work in terms of its efficiency and head, was also discussed in detail, leading to the conclusion on the optimal blade thickness and angle for the improvement of the performance. In addition, the total pressure loss coefficient was considered in order to investigate the loss within the flow paths depending on the thickness and angle variations. The results presented in this study may give guidelines to the numerical analysis of the axial-flow pump and the investigation of the performance for further optimal design of the axial-flow pump.

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