Effect of parameter mismatch and dissipative coupling on amplitude death regime in a coupled nonlinear aeroelastic system

2021 ◽  
Vol 31 (12) ◽  
pp. 123112
Author(s):  
Arvind Raj ◽  
Ashwad Raaj ◽  
J. Venkatramani ◽  
Sirshendu Mondal
Keyword(s):  
Amplitude Death ◽  
Parameter Mismatch ◽  
Aeroelastic System

Investigating amplitude death in a coupled nonlinear aeroelastic system

2021 ◽  
Vol 129 ◽  
pp. 103659
Author(s):  
Ashwad Raaj ◽  
Sirshendu Mondal ◽  
Venkatramani Jagdish
Keyword(s):  
Amplitude Death ◽  
Aeroelastic System

Effect of parameter mismatch and time delay interaction on density-induced amplitude death in coupled nonlinear oscillators

2014 ◽  
Vol 76 (3) ◽  
pp. 1797-1806 ◽  
Author(s):  
Amit Sharma ◽  
K. Suresh ◽  
K. Thamilmaran ◽  
Awadhesh Prasad ◽  
Manish Dev Shrimali
Keyword(s):  
Time Delay ◽  
Nonlinear Oscillators ◽  
Amplitude Death ◽  
Parameter Mismatch ◽  
Coupled Nonlinear Oscillators ◽  
Delay Interaction

Impulsive synchronization and parameter mismatch of the three-variable autocatalator model

2007 ◽  
Vol 366 (1-2) ◽  
pp. 52-60 ◽  
Author(s):  
Yang Li ◽  
Xiaofeng Liao ◽  
Chuandong Li ◽  
Tingwen Huang ◽  
Degang Yang
Keyword(s):  
Parameter Mismatch ◽  
Impulsive Synchronization

scholarly journals A Modified Model Predictive Torque Control with Parameters Robustness Improvement for PMSM of Electric Vehicles

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 132
Author(s):  
Siyu Gao ◽  
Yanjun Wei ◽  
Di Zhang ◽  
Hanhong Qi ◽  
Yao Wei
Keyword(s):  
Real Time ◽  
Torque Ripple ◽  
Torque Control ◽  
Parameter Mismatch ◽  
Modified Model ◽  
Simulation And Experiment ◽  
Drive Systems ◽  
Low Torque ◽  
Time Update ◽  
Model Reference Adaptive

Model predictive torque control with duty cycle control (MPTC-DCC) is widely used in motor drive systems because of its low torque ripple and good steady-state performance. However, the selection of the optimal voltage vector and the calculation of the duration are extremely dependent on the accuracy of the motor parameters. In view of this situation, A modified MPTC-DCC is proposed in this paper. According to the variation of error between the measured value and the predicted value, the motor parameters are calculated in real-time. Meanwhile, Model reference adaptive control (MRAC) is adopted in the speed loop to eliminate the disturbance caused by the ripple of real-time update parameters, through which the disturbance caused by parameter mismatch is suppressed effectively. The simulation and experiment are carried out on MATLAB / Simulink software and dSPACE experimental platform, which corroborate the principle analysis and the correctness of the method.

scholarly journals Experimental Observation of the Amplitude Death Effect in Two Coupled Nonlinear Oscillators

2000 ◽  
Vol 84 (23) ◽  
pp. 5312-5315 ◽  
Author(s):  
R. Herrero ◽  
M. Figueras ◽  
J. Rius ◽  
F. Pi ◽  
G. Orriols
Keyword(s):  
Experimental Observation ◽  
Nonlinear Oscillators ◽  
Amplitude Death ◽  
Coupled Nonlinear Oscillators

scholarly journals A Combined Energy Method for Flutter Instability Analysis of Weakly Damped Panels in Supersonic Airflow

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1090
Author(s):  
Xiaochen Wang ◽  
Zhichun Yang ◽  
Guiwei Zhang ◽  
Xinwei Xu
Keyword(s):  
Energy Balance ◽  
Energy Method ◽  
Plate Theory ◽  
Dynamic Pressure ◽  
Physical Nature ◽  
Aeroelastic System ◽  
Dissipation Energy ◽  
Supersonic Airflow ◽  
Flutter Instability ◽  
Modal Damping

A combined energy method is proposed to investigate the flutter instability characteristics of weakly damped panels in the supersonic airflow. Based on the small damping assumption, the motion governing partial differential equation (PDE) of the panel aeroelastic system, is built by adopting the first-order piston theory and von Karman large deflection plate theory. Then by applying the Galerkin procedure, the PDE is discretized into a set of coupled ordinary differential equations, and the system reduced order model (ROM) with two degrees of freedom is obtained. Considering that the panel aeroelastic system is non-conservative in the physical nature, and assuming that the panel exhibits a single period oscillation on the flutter occurrence, the non-conservative energy balance principle is applied to the linearized ROM within one single oscillation period. The obtained result shows that the ROM modal coordinate amplitudes ratio is regulated by the modal damping coefficients ratio, though each modal damping coefficient is small. Furthermore, as the total damping dissipation energy can be eliminated due to its smallness, the He’s energy balance method is applied to the undamped ROM, therefore the critical non-dimensional dynamic pressure on the flutter instability occurrence, and the oscillation circular frequency amplitude relationship (linear and nonlinear form) are derived. In addition, the damping destabilization paradoxical influence on the system flutter instability is investigated. The accuracy and efficiency of the proposed method are validated by comparing the results with that obtained by using Routh Hurwitz criteria.

scholarly journals Comparison of Two Numerical Algorithms for Computing the Effects of Mistuning of Fan Flutter

2016 ◽  
Author(s):  
L. Salles ◽  
M. Vahdati
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Mode Shapes ◽  
Minimal Amount ◽  
Aeroelastic System ◽  
Cpu Time ◽  
Influence Coefficients ◽  
Non Linear ◽  
The Time Domain

The aim of this paper is to study the effects of mistuning on fan flutter and to compare the prediction of two numerical models of different fidelity. The high fidelity model used here is a three-dimensional, whole assembly, time-accurate, viscous, finite-volume compressible flow solver. The Code used for this purpose is AU3D, written in Imperial College and validated for flutter computations over many years. To the best knowledge of authors, this is the first time such computations have been attempted. This is due to the fact that, such non-linear aeroelastic computations with mistuning require large amount of CPU time and cannot be performed routinely and consequently, faster (low fidelity) models are required for this task. Therefore, the second model used here is the aeroelastic fundamental mistuning model (FMM) and it based on an eigenvalue analysis of the linearized modal aeroelastic system with the aerodynamic matrix calculated from the aerodynamic influence coefficients. The influence coefficients required for this algorithm are obtained from the time domain non-linear Code by shaking one blade in the datum (tuned) frequency and mode. Once the influence coefficients have been obtained, the computations of aero damping require minimal amount of CPU time and many different mistuning patterns can be studied. The objectives of this work are to: 1. Compare the results between the two models and establish the capabilities/limitations of aeroelastic FMM, 2. Check if the introduction of mistuning would bring the experimental and computed flutter boundaries closer, 3. Establish a relationship between mistuning and damping. A rig wide-chord fan blade, typical of modern civil designs, was used as the benchmark geometry for this study. All the flutter analyses carried out in this paper are with frequency mistuning, but the possible consequences of mistuned mode shapes are briefly discussed at the end of this paper. Only the first family of modes (1F, first flap) is considered in this work. For the frequency mistuning analysis, the 1F frequency is varied around the annulus but the 1F mode shapes remain the same for all the blades. For the mode shape mistuning computations, an FE analysis of the whole assembly different mass blades is performed. The results of this work clearly show the importance of mistuning on flutter. It also demonstrates that when using rig test data for aeroelastic validation of CFD codes, the amount mistuning present must be known. Finally, it should be noted that the aim of this paper is the study of mistuning and not steady/unsteady validation of a CFD code and therefore minimal aerodynamic data are presented.

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