969 research outputs found
Vortex phase matching of a self-propelled model of fish with autonomous fin motion
It has been a long-standing problem how schooling fish optimize their motion
by exploiting the vortices shed by the others. A recent experimental study
showed that a pair of fish reduce energy consumption by matching the phases of
their tailbeat according to their distance. In order to elucidate the dynamical
mechanism by which fish control the motion of caudal fins via vortex-mediated
hydrodynamic interactions, we introduce a new model of a self-propelled swimmer
with an active flapping plate. The model incorporates the role of the central
pattern generator network that generates rhythmic but noisy activity of the
caudal muscle, in addition to hydrodynamic and elastic torques on the fin. For
a solitary fish, the model reproduces a linear relation between the swimming
speed and tailbeat frequency, as well as the distributions of the speed,
tailbeat amplitude, and frequency. For a pair of fish, both the distribution
function and energy dissipation rate exhibit periodic patterns as functions of
the front-back distance and phase difference of the flapping motion. We show
that a pair of fish spontaneously adjust their distance and phase difference
via hydrodynamic interaction to reduce energy consumption.Comment: 18 pages, 11 figure
"Shin" as Pure Passivity
とある研究会でのこと。西欧中世を代表する神学者・哲学者の愛について解釈を展開していた論者が、人間は本来エゴイスティックな生きものであり、そのような人間にとって愛は当為として意義づけられると述べていた。 ..
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