Study of a stall induced dynamical system under gust using the probability density evolution technique

Devathi, Harshini; Sarkar, Saswati

doi:10.1016/j.compstruc.2015.09.003

Cited by 16 publications

(6 citation statements)

References 37 publications

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“…The corresponding frequency response of these RLCOs has a single dominant peak closer to f α . This implies that the two modes coalesce near f α resulting in pitch dominant LCOs akin to the deterministic scenario, and hence these LCOs can be termed as stochastic stall flutter 40 .…”

Section: Dynamic Characterization Of Fluttermentioning

confidence: 99%

Experimental investigation on the synchronization characteristics of a pitch-plunge aeroelastic system exhibiting stall flutter

Tripathi

Shreenivas

Bose

et al. 2022

Chaos: An Interdisciplinary Journal of Nonlinear Science

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This study focuses on characterizing the bifurcation scenario and the underlying synchrony behavior in a nonlinear aeroelastic system under deterministic as well as stochastic inflow conditions. Wind tunnel experiments are carried out for a canonical pitch-plunge aeroelastic system subjected to dynamic stall conditions. The system is observed to undergo a subcritical Hopf bifurcation, giving way to large-amplitude limit cycle oscillations (LCOs) in the stall flutter regime under the deterministic flow conditions. At this condition, we observe intermittent phase synchronization between pitch and plunge modes near the fold point, whereas synchronization via phase trapping is observed near the Hopf point. Repeating the experiments under stochastic inflow conditions, we observe two different aeroelastic responses: low amplitude noise-induced random oscillations (NIROs) and high-amplitude random LCOs (RLCOs) during stall flutter. The present study shows asynchrony between pitch and plunge modes in the NIRO regime. At the onset of RLCOs, asynchrony persists even though the relative phase distribution changes. With further increase in the flow velocity, we observe intermittent phase synchronization in the flutter regime. To the best of the authors’ knowledge, this is the first study reporting the experimental evidence of phase synchronization between pitch and plunge modes of an aeroelastic system, which is of great interest to the nonlinear dynamics community. Furthermore, given the ubiquitous presence of stall behavior and stochasticity in a variety of engineering systems, such as wind turbine blades, helicopter blades, and unmanned aerial vehicles, the present findings will be directly beneficial for the efficient design of futuristic aeroelastic systems.

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Section: Dynamic Characterization Of Fluttermentioning

confidence: 99%

Experimental investigation on the synchronization characteristics of a pitch-plunge aeroelastic system exhibiting stall flutter

Tripathi

Shreenivas

Bose

et al. 2022

Chaos: An Interdisciplinary Journal of Nonlinear Science

View full text Add to dashboard Cite

show abstract

“…Alternatively, semi-empirical models, such as LB model [35] are capable of estimating the loads with an agreeable extent of accuracy while considerably reducing the computation cost. They are widely used in the literature for aeroelastic computations of systems subjected to dynamic stall [10,12,14,15]. Accordingly, the present study uses the LB model to estimate the loads at dynamic stall regimes.…”

Section: Aerodynamic Modelmentioning

confidence: 99%

“…The fluctuations in the longitudinal inflow are generated using the Karhunen-Loeve expansion (KLE) approach using a prescribed correlation [15,25]. In KLE, a stochastic process is simulated as bi-orthogonal decomposition of its correlation function [26].…”

Section: Karhunen-loeve Expansion For Fluctuating Inflowmentioning

confidence: 99%

“…However, in actual field conditions, aerodynamic loads on structures like wind turbines and helicopter rotor blades are often highly stochastic in nature due to the variation of flow speed with time and/or height in the atmospheric boundary layer. Recent studies by Bethi et al [14], and Devathi and Sarkar [15] highlight the significance of adopting a stochastic flow model and studying the subsequent impact on the aeroelastic response dynamics. The authors have shown the presence of noise-induced intermittency (NII) even at low mean flow speeds, triggered due to the input flow fluctuations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stall-induced fatigue damage in nonlinear aeroelastic systems under stochastic inflow: Numerical and experimental analyses

Tripathi

Vishal

Bose

et al. 2022

International Journal of Non-Linear Mechanics

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“…An approximate Wiener path integral with an appropriately chosen expansion function has been developed in [13] for approximating the joint response pdf for multi-dofs. Based on the principle of preservation of probability, the probability density evolution method [19] is an alternative approach that has been developed for estimating the evolutionary joint pdf of the response variables and has been successfully implemented to complex multi-dofs systems [18] and other systems [5].…”

Section: Introductionmentioning

confidence: 99%

Targeted energy transfer in stochastically excited system with nonlinear energy sink

2018

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This study investigates the phenomenon of targeted energy transfer (TET) from a linear oscillator to a nonlinear attachment behaving as a nonlinear energy sink for both transient and stochastic excitations. First, the dynamics of the underlying Hamiltonian system under deterministic transient loading is studied. Assuming that the transient dynamics can be partitioned into slow and fast components, the governing equations of motion corresponding to the slow flow dynamics are derived and the behaviour of the system is analysed. Subsequently, the effect of noise on the slow flow dynamics of the system is investigated. The Itô stochastic differential equations for the noisy system are derived and the corresponding Fokker–Planck equations are numerically solved to gain insights into the behaviour of the system on TET. The effects of the system parameters as well as noise intensity on the optimal regime of TET are studied. The analysis reveals that the interaction of nonlinearities and noise enhances the optimal TET regime as predicted in deterministic analysis.

show abstract

Study of a stall induced dynamical system under gust using the probability density evolution technique

Cited by 16 publications

References 37 publications

Experimental investigation on the synchronization characteristics of a pitch-plunge aeroelastic system exhibiting stall flutter

Experimental investigation on the synchronization characteristics of a pitch-plunge aeroelastic system exhibiting stall flutter

Stall-induced fatigue damage in nonlinear aeroelastic systems under stochastic inflow: Numerical and experimental analyses

Targeted energy transfer in stochastically excited system with nonlinear energy sink

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