Canard explosions in turbulent thermo-fluid systems

Fuente: arXiv
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Main Authors: Bhavi, Ramesh S., Sudarsanan, Sivakumar, Raghunathan, Manikandan, Bhaskaran, Anaswara, Sujith, R. I.
Format: Preprint
Published: 2024
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author Bhavi, Ramesh S.
Sudarsanan, Sivakumar
Raghunathan, Manikandan
Bhaskaran, Anaswara
Sujith, R. I.
author_facet Bhavi, Ramesh S.
Sudarsanan, Sivakumar
Raghunathan, Manikandan
Bhaskaran, Anaswara
Sujith, R. I.
contents A sudden transition to a state of high amplitude limit cycle oscillations is catastrophic in a thermo-fluid system. Conventionally, upon varying the control parameter, a sudden transition is observed as an abrupt jump in the amplitude of the fluctuations in these systems. In contrast, we present an experimental discovery of a canard explosion in a turbulent reactive flow system where we observe a continuous bifurcation with a rapid rise in the amplitude of the fluctuations within a narrow range of control parameters. The observed transition is facilitated via a state of bursting, consisting of the epochs of large amplitude periodic oscillations amidst the epochs of low amplitude periodic oscillations. The amplitude of the bursts is higher than the amplitude of the bursts of intermittency state in a conventional gradual transition, as reported in turbulent reactive flow systems. During the bursting state, we observe that temperature fluctuations of exhaust gas vary at a slower time scale in correlation with the amplitude envelope of the bursts. We also present a phenomenological model for thermoacoustic systems to describe the observed canard explosion. Using the model, we explain that the large amplitude bursts occur due to the slow-fast dynamics at the bifurcation regime of the canard explosion.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08599
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Canard explosions in turbulent thermo-fluid systems
Bhavi, Ramesh S.
Sudarsanan, Sivakumar
Raghunathan, Manikandan
Bhaskaran, Anaswara
Sujith, R. I.
Fluid Dynamics
Adaptation and Self-Organizing Systems
Applied Physics
A sudden transition to a state of high amplitude limit cycle oscillations is catastrophic in a thermo-fluid system. Conventionally, upon varying the control parameter, a sudden transition is observed as an abrupt jump in the amplitude of the fluctuations in these systems. In contrast, we present an experimental discovery of a canard explosion in a turbulent reactive flow system where we observe a continuous bifurcation with a rapid rise in the amplitude of the fluctuations within a narrow range of control parameters. The observed transition is facilitated via a state of bursting, consisting of the epochs of large amplitude periodic oscillations amidst the epochs of low amplitude periodic oscillations. The amplitude of the bursts is higher than the amplitude of the bursts of intermittency state in a conventional gradual transition, as reported in turbulent reactive flow systems. During the bursting state, we observe that temperature fluctuations of exhaust gas vary at a slower time scale in correlation with the amplitude envelope of the bursts. We also present a phenomenological model for thermoacoustic systems to describe the observed canard explosion. Using the model, we explain that the large amplitude bursts occur due to the slow-fast dynamics at the bifurcation regime of the canard explosion.
title Canard explosions in turbulent thermo-fluid systems
topic Fluid Dynamics
Adaptation and Self-Organizing Systems
Applied Physics
url https://arxiv.org/abs/2406.08599