FORMA
Online ISSN : 2189-1311
Print ISSN : 0911-6036
Volume 34, Issue 1
Displaying 1-3 of 3 articles from this issue
Forum
Letter
  • Takashi Yoshino
    Article type: research-article
    2019Volume 34Issue 1 Pages 5-12
    Published: 2019
    Released on J-STAGE: August 21, 2023
    JOURNAL FREE ACCESS

    We derived the Stokes equations and velocity potential around a hyperspherical obstacle in n-dimensional space. The objectives of this study were to understand the hyperspace through the physics in the space and to bring the analytical solution of fluid flow in hyperspace for numerical simulation. The equations were obtained from the n-dimensional Navier-Stokes equation assuming the low Reynolds number flow. These were generalized formulae from a 3-dimensional system to an n-dimensional one. Our results show that the effect of the hyperspherical obstacle on the uniform flow is localized in higher dimensional spaces. We visualized the flow using the collections of hypersections.

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  • Toru Tanimura, Yusuke Jono, Takayuki Hirata, Yasuyuki Matsuura, Hiroki ...
    Article type: research-article
    2019Volume 34Issue 1 Pages 13-20
    Published: 2019
    Released on J-STAGE: August 21, 2023
    JOURNAL FREE ACCESS

    The nonlinearity of the mathematical model describing the cerebral blood flow dynamics and the body sway in the prefrontal cortex was investigated experimentally. The measured bio-signal data were smoothed with each low-pass filter. The signal was set to 0.1-2 Hz for the cerebral blood flow dynamics and to 0.1-20 Hz for the body sway. Nonlinearity was observed in the biological signal when the cut-off frequency of the low-pass filtering was 0.2 Hz or less, and while the body sway was 0.5 Hz or less, and was considered as a stochastic differential equations.

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