title: Memory function of turbulent fluctuations in soft-mode turbulence.
abstract: Modal relaxation dynamics has been observed experimentally to clarify statistical-physical properties of soft-mode turbulence, the spatiotemporal chaos observed in homeotropically aligned nematic liquid crystals. We found a dual structure, dynamical crossover associated with violation of time-reversal invariance, the corresponding time scales satisfying a dynamical scaling law. To specify the origin of the dual structure, the memory function due to nonthermal fluctuations has been defined by a projection-operator method and obtained numerically using experimental results. The results of the memory function suggest that the nonthermal fluctuations can be divided into Markov and non-Markov contributions; the latter is called the turbulent fluctuation (TF). Consequently, the relaxation dynamics is separated into three characteristic stages: bare-friction, early, and late stages. If the dissipation due to TFs dominates over that of the Markov contribution, the bare-friction stage contracts; the early and late stages then configure the dual structure. The memory effect due to TFs results in a time-reversible relaxation at the early stage, and the disappearance of the memory by turbulent mixing leads to a simple exponential relaxation at the late stage. Furthermore, the memory effect due to TFs is shown to originate from characteristic spatial coherency called the patch structure.
authors: Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan. narumi@athena.ap.kyushu-u.ac.jp
authors: Takayuki
authors: T
authors: Narumi
authors: Junichi
authors: J
authors: Yoshitani
authors: Masaru
authors: M
authors: Suzuki
authors: Yoshiki
authors: Y
authors: Hidaka
authors: Fahrudin
authors: F
authors: Nugroho
authors: Tomoyuki
authors: T
authors: Nagaya
authors: Shoichi
authors: S
authors: Kai
mesh_terms: D003198:Computer Simulation; D016247:Information Storage and Retrieval / Q000379:methods*; D050866:Liquid Crystals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical