Journal ArticleDOI
Coupled interaction between unsteady flame dynamics and acoustic field in a turbulent combustor
Vedasri Godavarthi,Samadhan A. Pawar,Vishnu R. Unni,R. I. Sujith,Norbert Marwan,Jürgen Kurths,Jürgen Kurths,Jürgen Kurths +7 more
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TLDR
A possible asymmetric bidirectional coupling between q ˙ ' and p ' is observed to exert a stronger influence on p ' than vice versa, and the directional property of the network measure, namely, cross transitivity is used to analyze the type of coupling existing between the acoustic field and the heat release rate fluctuations.Abstract:
Thermoacoustic instability is a result of the positive feedback between the acoustic pressure and the unsteady heat release rate fluctuations in a combustor. We apply the framework of the synchronization theory to study the coupled behavior of these oscillations during the transition to thermoacoustic instability in a turbulent bluff-body stabilized gas-fired combustor. Furthermore, we characterize this complex behavior using recurrence plots and recurrence networks. We mainly found that the correlation of probability of recurrence ( C P R), the joint probability of recurrence ( J P R), the determinism ( D E T), and the recurrence rate ( R R) of the joint recurrence matrix aid in detecting the synchronization transitions in this thermoacoustic system. We noticed that C P R and D E T can uncover the occurrence of phase synchronization state, whereas J P R and R R can be used as indices to identify the occurrence of generalized synchronization (GS) state in the system. We applied measures derived from joint and cross recurrence networks and observed that the joint recurrence network measures, transitivity ratio, and joint transitivity are useful to detect GS. Furthermore, we use the directional property of the network measure, namely, cross transitivity to analyze the type of coupling existing between the acoustic field ( p ′) and the heat release rate ( q ˙ ′) fluctuations. We discover a possible asymmetric bidirectional coupling between q ˙ ′ and p ′, wherein q ˙ ′ is observed to exert a stronger influence on p ′ than vice versa.Thermoacoustic instability is a result of the positive feedback between the acoustic pressure and the unsteady heat release rate fluctuations in a combustor. We apply the framework of the synchronization theory to study the coupled behavior of these oscillations during the transition to thermoacoustic instability in a turbulent bluff-body stabilized gas-fired combustor. Furthermore, we characterize this complex behavior using recurrence plots and recurrence networks. We mainly found that the correlation of probability of recurrence ( C P R), the joint probability of recurrence ( J P R), the determinism ( D E T), and the recurrence rate ( R R) of the joint recurrence matrix aid in detecting the synchronization transitions in this thermoacoustic system. We noticed that C P R and D E T can uncover the occurrence of phase synchronization state, whereas J P R and R R can be used as indices to identify the occurrence of generalized synchronization (GS) state in the system. We applied measures derive...read more
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Journal ArticleDOI
Synchronization transition from chaos to limit cycle oscillations when a locally coupled chaotic oscillator grid is coupled globally to another chaotic oscillator.
Vedasri Godavarthi,Praveen Kasthuri,Sirshendu Mondal,R. I. Sujith,Norbert Marwan,Jürgen Kurths +5 more
TL;DR: This model can be used to perform inexpensive numerical control experiments to suppress synchronization and thereby to mitigate unwanted oscillations in physical systems and report the existence of symmetry breaking phenomena during this transition from desynchronized chaos to synchronized periodicity.
Journal ArticleDOI
Condensation in the phase space and network topology during transition from chaos to order in turbulent thermoacoustic systems.
Shruti Tandon,R. I. Sujith +1 more
TL;DR: The use of network centrality measures derived from cycle networks are proposed as a novel means to characterize the number and stability of periodic orbits in the phase space and to study the topological transformations in thephase space during the emergence of order from chaos in the combustors.
Journal ArticleDOI
Synchronization framework for modeling transition to thermoacoustic instability in laminar combustors
TL;DR: In this article, a model based on the framework of synchronization was proposed to describe a thermoacoustic system and capture the multiple bifurcations that such a system undergoes.
Journal ArticleDOI
Early detection of thermoacoustic instabilities in a cryogenic rocket thrust chamber using combustion noise features and machine learning
Günther Waxenegger-Wilfing,Ushnish Sengupta,Jan Martin,Wolfgang Armbruster,Justin Hardi,Matthew P. Juniper,Michael Oschwald +6 more
TL;DR: In this paper, a data-driven method for the early detection of thermoacoustic instabilities is presented, which is used to calculate characteristic combustion features from short-length time series of dynamic pressure sensor data.
Posted Content
Coupled interaction between acoustics and unsteady flame dynamics during the transition to thermoacoustic instability in a multi-element rocket combustor
TL;DR: In this article, the authors study the coupled interaction between the acoustic pressure and the CH* intensity oscillations in a 2D multi-element self-excited model rocket combustor during the transition from a stable state to thermoacoustic instability through intermittency.
References
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Dynamical assessment of physiological systems and states using recurrence plot strategies
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Recurrence-plot-based measures of complexity and their application to heart-rate-variability data.
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