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TOMOO KATSUYAMA

Department of Physics, Namazu College of Technology

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Last update 2 Feb. 2005

Conferences on Chaos and Neuro-physics (or Physics in general):

A jet flow from a hair drier/ by the shadowgraph method.

MY RESEARCH INTERESTS fall in the general category of CHAOS. I am now specially interested in the following subjects:

(1) Scaling property and intermittency of turbulent velocity

I am investigating into intermittency of turbulence. The Gabor transform, a numerical band-pass filter, is extremely useful to analyze the scaling property of moderate-Reynolds-number turbulence. By applying the Gabor transform to the scaling analysis, I elucidated that the intermittency of turbulence is the viscous breakdown of the self-similarity.

(2) Time series analysis of heartbeat (BiPaC project)

The interval of heartbeat exhibits a great variety of fluctuations in spite of its remarkable regularity. Through the analysis of the fluctuations, BiPac group, including cardiologists, physicists, biologists, etc., makes an attempt at clarifying the heart regulation mechanism. A heart of a hermit crab Aniculus aniculus is carefully controlled in the stable condition. We get heartbeat signals from it and investigate the dynamical behavior of the signals by means of the time-series analysis.

(3) Chaos in a dripping faucet

Various aspects of nonlinear dynamics, chaotic oscillation, bifurcation, intermittency, etc., can be observed in a time series of the interval of drips falling from a leaky faucet. Dripping behavior dramatically changes with the flow rate. In the time series measured at carefully controlled flow-rates, I found that the dripping spectrum, a graph of drop interval vs. flow rate, repeatedly shows a periodic state and a chaotic state with increasing flow rate.

Details can be found in the following papers.

• T. Katsuyama, Y. Horiuchi, and K. Nagata; Phys. Rev. E 49, 4052-4059(1994). "Intermittency and scaling property of band-pass-filtered signals in moderate-Raynolds-number turbulent flows". (Theme 1)
• T. Katsuyama, M. Inoue, and K. Nagata; Phys. Rev. E 51, 5571-5576(1995). "Gabor transform and intermittency in turbulence". Abstract. Theme(1).
• K. Nagata and T. Katsuyama; Phys. Rev. E 52, 2546-2548(1995). "Intermittency effects inherent in turbulence". Abstract. Theme(1).
• T. Katsuyama and K. Nagata; J. Phys. Soc. Jpn. 65, 3202-3207 (1996). "Intermittency in the Process of Turbulence Evolution in a Free Jet Flow". Abstract. Theme(1).
• T. Katsuyama and K. Nagata; J. Phys. Soc. Jpn. 68,396-400(1999). "Behavior of the dripping faucet over a wide range of the flow rate". Abstract. Theme(3).
• T. Yazawa and T. Katsuyama; J. Comp. Physiol. A187(2001), pp.817-824.; "Spontaneous and repetitive cardiac slowdown in the freely moving spiny lobster, Panulirus japonicus". Abstract. Theme(2).
• T. Katsuyama, K. Kiyono and N. Fuchikami;Theor. Appl. Mech. Jpn. 51(2002), pp.381-385.; "Chaos in a dripping tap". Abstract. Theme(3)
• T. Katsuyama, T. Masunaga, K. Kiyono and N. Fuchikami; Numazu College of Technoligy Research Annual 37(2002) pp215-219. "Chaotic dynamics of a dripping faucet".　Theme(3).
• T. Katsuyama, T. Nagaoka, K. Kiyono, K. Tanaka, I. Nakatani, T. Yazawa; Comp. Biochem. Physiol.A134(2003)232. "Non-linear cardiac rhythm regulation: Period doubling of heartbeat interval in mutant-white crayfish, Procambarus clarkii". Theme(2).
• K. Kiyono, T. Katsuyama, T. Masunaga and N. Fuchikami; Phys. Lett. A320:47-52, 2003. "Picture of the low-dimensional structure in chaotic dripping faucets". Theme(3).
• T. Katsuyama, T. Yazawa and K. Kiyono; Comp Biochem Physiol B136(2003)567. "Scaling analysis of heartbeat fluctuation of spiny lobster, Panulirus japonicus". Theme(2).

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