Review
Engineering, Aerospace
Jeet Panchal, Haym Benaroya
Summary: In recent decades, there has been growing interest in the field of nonlinear aeroelasticity, particularly in revisiting the control surface freeplay problem with improved computing capabilities. Modern theoretical and experimental analyses have led to various modeling approaches, but differing numerical predictions persist in the study of aeroelastic dynamical behavior and properties related to freeplay.
PROGRESS IN AEROSPACE SCIENCES
(2021)
Article
Engineering, Aerospace
Madhusudan A. Padmanabhan, Earl H. Dowell
Summary: This work explores the similar dynamic behavior of landing gears and all-movable control surfaces, which both exhibit shimmy/flutter limit cycle oscillations due to stiffness and damping nonlinearities. The authors extend their computational methods to systems with multiple nonlinearities and focus on the physical insights obtained. The results reveal the contribution of specific nonlinearities to the landing gear response and the shaping and modification of the flutter response in all-movable surfaces. The findings also provide a reinterpretation of wind tunnel flutter tests for all-movable horizontal tails.
JOURNAL OF AIRCRAFT
(2023)
Article
Engineering, Mechanical
Y. M. Chen, W. L. Li, B. F. Yan, J. K. Liu
Summary: Freeplay in the aeroelastic system of an airfoil with a control surface can significantly influence aeroelastic behavior, reducing the flow velocity at which a limit cycle may arise. A method based on eigenvalue analysis of a generalized Jacobian matrix has been proposed to easily calculate the lowest velocity and detect multiple subcritical LCs. The method can also determine the occurrence of subcritical LCs and distinguish between subcritical and supercritical LCs using the distribution of positive real parts.
NONLINEAR DYNAMICS
(2021)
Article
Chemistry, Multidisciplinary
Liuyue Bai, Zhigang Wu, Chao Yang
Summary: This study provides novel perspectives on the nonlinear aeroelastic characteristics of all-movable fins with freeplay nonlinearities. An unsteady aerodynamic model based on the second-order piston theory considering thickness effects is employed. A discrete scanning method using the describing function method is established for systems with multiple freeplay nonlinearities to solve limit-cycle oscillations (LCOs) and avoid solution loss. The influence of support stiffness and freeplay size ratio on the system's dynamical response is analyzed.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Multidisciplinary
Xiangyu Wang, Zhigang Wu, Chao Yang
Summary: This study introduces a state space iterating scheme to efficiently find limit cycle solutions using time integrations, visually depicts system behaviors through a combination of modified Poincare and Lorenz maps, and verifies its ability to find LCOs in aeroelastic systems.
APPLIED SCIENCES-BASEL
(2021)
Article
Acoustics
Moshan Guo, Gangtie Zheng
Summary: This paper presents a novel explanation on the aerodynamic function of the dragonfly stigma, which is a pigmented spot with heavier masses near the tip of a dragonfly's wing. Dynamic modeling based on the micro-structures shows that the stigma can be simplified as two lumped masses connected by a massless beam, and installed on the primary structure by two tow springs. Theoretical modeling and numerical simulations prove that the stigma is capable to suppress flutter - a self-excited vibration.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Engineering, Mechanical
Christian Berthold, Johann Gross, Christian Frey, Malte Krack
Summary: Flutter stability is a key constraint in the design of modern gas and steam turbines. Current exploration involves designs that can tolerate flutter and explain bounded self-excited oscillations through nonlinear interactions. Developing a fully-coupled nonlinear frequency domain method allows for resolving nonlinear flow and structural effects efficiently.
JOURNAL OF FLUIDS AND STRUCTURES
(2021)
Article
Mathematics, Interdisciplinary Applications
Saumen Chakraborty, Manaj Dandapathak, Saumendra Sankar De Sarkar
Summary: In this study, a self-feedback control scheme is proposed to achieve oscillation quenching or retrieve rhythmic behavior, providing better control on the dynamics of the mean-field coupled system. Additionally, a transition phenomenon from inhomogeneous limit cycle (IHLC) to homogeneous limit cycle (HLC) through chaotic route has been observed in the modified system.
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS
(2021)
Article
Acoustics
Gautam Kumar, Anindya Malas
Summary: In this study, the effectiveness of acceleration feedback control in mitigating friction-induced mode-coupling instability is theoretically investigated, with optimized filter parameters and control laws stabilizing the system and reducing instability in nonlinear systems.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Engineering, Mechanical
Keum W. Lee, Sahjendra N. Singh
Summary: The paper introduces a generalized composite noncertainty-equivalence adaptive control system for aeroelastic wing section, aiming to suppress oscillatory responses using a composite integral parameter estimation law based on immersion and invariance theory and classical adaptive algorithms. Simulation results demonstrate successful suppression despite uncertainties in model parameters.
NONLINEAR DYNAMICS
(2021)
Article
Engineering, Mechanical
Maxim Freydin, Earl H. Dowell, S. Michael Spottswood, Ricardo A. Perez
Summary: The transient response of a plate and a cavity in a supersonic wind tunnel experiment was investigated, showing flutter onset, transition to limit cycle oscillation, and stabilization. A fully coupled aero-thermal-acousto-elastic analysis was performed, including linear stability analysis and direct time integration of nonlinear fluid structural equations. The system's sensitivity to various factors and snap-through buckling analyses in response to excitations were also investigated.
NONLINEAR DYNAMICS
(2021)
Article
Acoustics
Chengde Huang, Jie Huang, Xin Song, Guannan Zheng, Guowei Yang
Summary: The paper introduces a framework of CFD/CSD coupling approach to handle three-dimensional aeroelastic problems, effectively predicting stable limit cycle oscillation. Results demonstrate that the LCO behavior is subcritical and viscous effect increases the LCO boundary.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Mathematics, Applied
Bo Wu, Huoming Shen, Haili Liao, Qi Wang, Yan Zhang, Zhiguo Li
Summary: This study comprehensively investigates the intrinsic time-varying nonlinear aerodynamic properties and actual energy feedback mechanism of limit cycle oscillation (LCO) and subcritical Hopf bifurcation, which are crucial for flutter design of bridges. The nonlinear flutter response characteristics were experimentally investigated. The dynamic mechanism of subcritical Hopf bifurcation was introduced, and a modified nonlinear self-excited force model was proposed to study the intrinsic time-varying characteristics and energy feedback mechanism of subcritical Hopf bifurcation. The energy feedback mechanisms of LCO and subcritical Hopf bifurcation were qualitatively discussed, and the driving mechanisms were explained quantitatively through an energy budget analysis.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2022)
Review
Neurosciences
Lingyun (Ivy) Xiong, Alan Garfinkel
Summary: This article argues that oscillations play critical physiological roles in avoiding desensitization, maintaining balanced chemical levels, increasing resistance to noise, reconciling incompatible conditions, and synchronizing small units into one large effect. It also emphasizes the importance of a dynamic approach and nonlinear dynamics in understanding and studying oscillatory processes in various levels of biological systems.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Meteorology & Atmospheric Sciences
Bo-Wen Shen, Roger A. Pielke, Xubin Zeng, Jong-Jin Baik, Sara Faghih-Naini, Jialin Cui, Robert Atlas
Summary: This study explores the dual nature of chaos and order in weather systems based on the Generalized Lorenz Model (GLM), highlighting mechanisms that contribute to distinct predictability such as small-scale convective processes and large-scale time-varying forcing. The results suggest the coexistence of different types of attractors in weather, presenting new opportunities and challenges in improving predictions at extended-range and subseasonal to seasonal time scales.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
Daniel J. L. L. Pinheiro, Leandro F. Oliveira, Isis N. O. Souza, Joao A. Ferres Brogin, Douglas D. Bueno, Iranaia Assuncao Miranda, Andrea T. Da Poian, Sergio T. Ferreira, Claudia P. Figueiredo, Julia R. Clarke, Esper A. Cavalheiro, Jean Faber
SCIENTIFIC REPORTS
(2020)
Article
Computer Science, Artificial Intelligence
Joao Angelo Ferres Brogin, Jean Faber, Douglas Domingues Bueno
INTERNATIONAL JOURNAL OF NEURAL SYSTEMS
(2020)
Article
Engineering, Mechanical
Douglas D. Bueno, Camila G. Gonsalez Bueno, Earl H. Dowell
Summary: This article introduces an algebraic arrangement for designing a modal controller to suppress the flutter phenomenon, combined with a linear quadratic regulator to compute a control gain, which is converted from the new modal domain to the physical, introducing an effect of incremental damping. Numerical simulations are carried out to demonstrate that this technique allows stabilizing the system.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2021)
Article
Acoustics
J. P. Carneiro Jr, M. J. Brennan, P. J. P. Goncalves, V. G. Cleante, D. D. Bueno, R. B. Santos
Summary: It is found that correctly oriented asymmetric cells offer better performance than an array of symmetric cells for a finite mono-coupled periodic structure, improving the vibration attenuation. Predictions of the maximum attenuation within the attenuation band based on the number of symmetric or asymmetric cells can be made under appropriate conditions.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Engineering, Mechanical
Douglas D. Bueno, Earl H. Dowell
Summary: The article demonstrates a new approach for constructing a time domain state space model for aeroelastic systems without the explicit representation of unsteady aerodynamics. By utilizing linear algebra to iteratively obtain eigenvalues and eigenvectors from the pk method, accurate results for linear dynamic aeroelastic models in either physical or generalized coordinates are achieved. This approach provides an alternative method for obtaining state space models in aeroelastic analysis.
JOURNAL OF FLUIDS AND STRUCTURES
(2021)
Article
Mechanics
Rodrigo Borges Santos, Jean Paulo Carneiro Junior, Camila Gianini Gonsalez-Bueno, Bruna Spila de Lucca, Douglas D. Bueno
Summary: The article presents a modeling approach for designing periodic beams, and the results demonstrate that five periodic cells generate an effect equivalent to an infinite periodic beam in terms of flexural vibration suppression.
Review
Engineering, Aerospace
Douglas D. Bueno, Larissa D. Wayhs-Lopes, Earl H. Dowell
Summary: This paper reviews and assesses more than six decades of research in aeroelastic stability, with a focus on control-surface nonlinearities. The basic modeling of each nonlinearity is introduced to provide insights for beginners in the field. The findings show that the two and three degrees of freedom typical section model has been extensively studied, and that nonlinearity in the pitch degree of freedom tends to generate more complex limit-cycle oscillations. The paper also presents the most commonly employed methods in theoretical and computational analyses, along with their pros and cons. Additionally, it explores the challenges yet to be overcome and opportunities for further studies.
Article
Acoustics
Renan S. Geronel, Earl H. Dowell, Douglas D. Bueno
Summary: This article investigates the dynamics of a quadcopter with a payload mass, including the vibration frequency of the payload. By obtaining non-dimensional equations of motion, a simple equation is established to estimate the oscillation frequency without solving the equation of motion in the time domain.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Computer Science, Artificial Intelligence
Joao Angelo Ferres Brogin, Jean Faber, Douglas Domingues Bueno
Summary: Epilepsy, a common brain disorder, is not effectively treated with conventional methods, prompting the use of computational neuroscience and models like Epileptor for theoretical study. Control techniques are being designed with challenges in fully understanding the model states, as researchers aim to improve efficiency in observing and controlling epileptic activities.
NEURAL COMPUTATION
(2021)
Article
Engineering, Aerospace
R. S. Geronel, R. M. Botez, D. D. Bueno
Summary: This paper uses mathematical modeling and control methods to investigate the flight performance of a UAV with payload and attachment system, and compares it with conventional UAVs.
AERONAUTICAL JOURNAL
(2023)
Article
Biochemical Research Methods
Noemi S. Araujo, Selvin Z. Reyes-Garcia, Joao A. F. Brogin, Douglas D. Bueno, Esper A. Cavalheiro, Carla A. Scorza, Jean Faber
Summary: This study characterized different types of epileptiform activities recorded in vitro from patients with temporal lobe epilepsy using Poincare map and Recurrence Quantitative Analysis. The results showed that interictal-like events (II) were more chaotic than periodic ictal spiking (PIS) activities. It also identified that each hippocampal subfield expressed II and PIS activities in a specific and different way. Additionally, the study simulated the transition between II and PIS activities using computational models.
PLOS COMPUTATIONAL BIOLOGY
(2022)
Article
Acoustics
Kayc W. Lopes, Camila G. Gonsalez-Bueno, Daniel J. Inman, Douglas D. Bueno
Summary: This article presents an approach to investigate the effects of damage on longitudinal waves in thin plates with oblique incidence. The approach includes numerical simulations and experimental tests to demonstrate the improvement of damage detection and determination of damage depth by adjusting sensor size. The findings contribute to improving the current state of the art in wave propagation.
Article
Engineering, Aerospace
Frederico A. Ribeiro, Earl H. Dowell, Douglas D. Bueno
Summary: This paper investigates the modeling of aeroelasticity problems and the method of obtaining a time-domain aeroelastic system using the Least Square method. It discusses the physical meanings of augmented aerodynamics states due to lag terms and proposes a phase error-based index to measure the accuracy of rational function approximations based on the number of lag terms. The proposal allows analysts to determine the number of lag parameters needed to establish a time-domain aeroelastic model of a specified accuracy.
JOURNAL OF AIRCRAFT
(2021)
Article
Engineering, Mechanical
Xuyi Jia, Chunlin Gong, Wen Ji, Chunna Li
Summary: A flow sensing method for real-time forecast of flow field in FSI systems using structural deformation is proposed in this study. The method utilizes multilayer POD to improve accuracy and deep neural network to map mode coefficients. The results show that the proposed method performs accurately in flow properties forecasting and is suitable for FSI systems with complex flow structures.
JOURNAL OF FLUIDS AND STRUCTURES
(2024)
Article
Engineering, Mechanical
Paulo H. N. Silva, Gustavo R. S. Assi
Summary: This paper presents an experimental study of fluid-structure interaction, demonstrating that the controlled rotation of rods can reduce mean drag and fluctuating lift forces simultaneously. By using a multi-objective genetic algorithm, the optimum rotation speeds were found, resulting in a more significant reduction in objectives and energy consumption. The contribution of each rod depends on its angular position and the flow conditions generated by the upstream control rods. The study clarifies the physical principles of the phenomenon and paves the way for technological applications.
JOURNAL OF FLUIDS AND STRUCTURES
(2024)
Article
Engineering, Mechanical
Yacine Manal, Pascal Hemon
Summary: Synchronized unsteady wall pressure measurements were performed on a full-scale circular chimney subjected to natural wind. The analysis of the pressure distribution using bi-orthogonal decomposition was crucial for the success of the processing. The results showed that atmospheric turbulence plays a significant role in the unsteady pressure response on the chimney, generating high levels of RMS pressure.
JOURNAL OF FLUIDS AND STRUCTURES
(2024)
Article
Engineering, Mechanical
Hironori Takeda, Yusuke Asai, Shunichi Ishida, Yasutoshi Taniguchi, Takuya Terahara, Kenji Takizawa, Yohsuke Imai
Summary: Wrinkling and creasing of an elastic membrane in a shear flow can be influenced by shear rate and membrane thickness. The deformation type can be determined by mechanical and geometrical effects of the membrane thickness, based on the geometrical consistency of the capsule surface.
JOURNAL OF FLUIDS AND STRUCTURES
(2024)
