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Memory function of turbulent fluctuations in soft-mode turbulence
Takayuki Narumi1, Junichi Yoshitani, Masaru Suzuki
1Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan. narumi@athena.ap.kyushu-u.ac.jp
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|February 16, 2013
Summary
Soft-mode turbulence in liquid crystals exhibits a dual relaxation structure due to nonthermal fluctuations. This study identifies turbulent fluctuations (TF) as key to understanding this complex dynamical crossover and time-reversal invariance violation.
Area of Science:
- Soft matter physics
- Nonlinear dynamics
- Liquid crystal physics
Background:
- Soft-mode turbulence, a form of spatiotemporal chaos, is observed in homeotropically aligned nematic liquid crystals.
- Understanding the statistical-physical properties of this phenomenon requires detailed analysis of modal relaxation dynamics.
Purpose of the Study:
- To investigate the modal relaxation dynamics in soft-mode turbulence.
- To clarify the statistical-physical properties and origins of the observed dual structure and time-reversal invariance violation.
Main Methods:
- Experimental observation of modal relaxation dynamics.
- Definition and numerical calculation of the memory function using a projection-operator method.
- Analysis of nonthermal fluctuations, including Markov and non-Markov contributions (turbulent fluctuations).
Main Results:
- A dual structure and dynamical crossover associated with time-reversal invariance violation were identified.
- Nonthermal fluctuations were decomposed into Markov and non-Markov (turbulent fluctuation) contributions.
- Relaxation dynamics were characterized by three stages: bare-friction, early, and late, with turbulent fluctuations significantly influencing the dynamics and leading to time-reversible and exponential relaxation stages.
Conclusions:
- Turbulent fluctuations (TF) are crucial for the dual relaxation structure in soft-mode turbulence.
- The memory effect from TF causes time-reversible relaxation at the early stage, while turbulent mixing leads to exponential relaxation at the late stage.
- The patch structure is identified as the origin of the memory effect due to turbulent fluctuations.
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