41 citations · 239 across the 22 of their papers we have counts for
23 papers
Diffusion Enhancement and Directional Suppression Induced by Reciprocal Flows
Yuki Koyano, Hiroyuki Kitahata, Takeshi Ooshida
Reciprocal flows repeatedly return fluid elements to their initial positions, producing no net advective transport on time average. Nevertheless, their interplay with diffusion giv…
Intrinsic speed characteristics of a self-propelled camphor disk under repulsive perturbations
Yuki Koyano, Jerzy Górecki, Hiroyuki Kitahata
Camphor is a well-studied material capable of generating self-propelled motion at a water surface, and the resulting dynamics can exhibit a wide range of behaviors. Here, we analyz…
Energetics-based model for a diffusiophoretic motion of a deformable droplet
Hiroyuki Kitahata, Yuki Koyano, Yasuaki Kobayashi +1
We construct a mathematical model for a diffusiophoretic motion of a deformable droplet, which is floating on a liquid surface and is driven by the surface tension gradient origina…
Modeling the time evolution of a camphor rotor perturbed by a stationary camphor source
Jerzy Gorecki, Yuki Koyano, Hiroyuki Kitahata
A self-propelled motion resulting from the dissipation of camphor molecules on the water surface has been attracting scientific attention for more than 200 years. A generally accep…
Simple mathematical model for a pairing-induced motion of active and passive particles
Hiroaki Ishikawa, Yuki Koyano, Hiroaki Ito +2
We propose a simple mathematical model that describes a pairing-induced motion of active and passive particles in a two-dimensional system, which is motivated by our previous paper…
Activity Induced Diffusion Recovery in Crowded Colloidal Suspension
Arnab Maiti, Yuki Koyano, Hiroyuki Kitahata +1
We show that the force generated by active enzyme molecules are strong enough to influence the dynamics of their surroundings under artificial crowded environments. We measured the…
Mathematical modeling for the synchronization of two interacting active rotors
Hiroyuki Kitahata, Yuki Koyano
We investigate the synchronization of active rotors. A rotor is composed of a free-rotating arm with a particle that releases a surface-active chemical compound. It exhibits self-r…
Anomalous diffusion and transport by a reciprocal convective flow
Yuki Koyano, Hiroyuki Kitahata
Under low-Reynolds-number conditions, dynamics of convection and diffusion are usually considered separately because their dominant spatial and temporal scales are different, but c…
Pairing-induced motion of source and inert particles driven by surface tension
Hiroaki Ishikawa, Yuki Koyano, Hiroyuki Kitahata +1
We experimentally and theoretically investigate systems with a pair of source and inert particles that interacts through the concentration field. The experimental system comprises…
Autonomous elastic microswimmer
Katsutomo Era, Yuki Koyano, Yuto Hosaka +3
A model of an autonomous three-sphere microswimmer is proposed by implementing a coupling effect between the two natural lengths of an elastic microswimmer. Such a coupling mechani…
Imperfect bifurcation in the rotation of a propeller-shaped camphor rotor
Yuki Koyano, Hiroyuki Kitahata
We investigated the bifurcation structure on the self-propelled motion of a camphor rotor at a water surface. The center of the camphor rotor was fixed by the axis, and it showed r…
Diffusion enhancement in a levitated droplet via oscillatory deformation
Yuki Koyano, Hiroyuki Kitahata, Koji Hasegawa +5
Recent experimental results indicate that mixing is enhanced by a reciprocal flow induced inside a levitated droplet with an oscillatory deformation [T. Watanabe et al. Sci. Rep. 8…
Spontaneous motion of a camphor particle with a triangular modification from a circle
Hiroyuki Kitahata, Yuki Koyano
The spontaneous motion of a camphor particle with a slight modification from a circle is investigated. The effect of the shape on the motion is examined by the perturbation method.…
On a simple model that explains inversion of a self-propelled rotor under periodic stop and release operations
Yuki Koyano, Hiroyuki Kitahata, Satoshi Nakata +1
We propose a simple mathematical model that describes the time evolution of a self-propelled object on a liquid surface using such variables as the object location, the surface con…
Diffusion in crowded colloids of particles cyclically changing their shapes
Yuki Koyano, Hiroyuki Kitahata, Alexander S. Mikhailov
A simple model of an active colloid consisting of dumbbell-shaped particles that cyclically change their length without propelling themselves is proposed and analyzed. At nanoscale…
Two floating camphor particles interacting through lateral capillary force
Yuhei Hirose, Yusuke Yasugahira, Mamoru Okamoto +4
We consider a mathematical model for a two-particle system driven by the spatial gradient of a concentration field of chemicals with conservative attractive interactions in one dim…
Bifurcation in the angular velocity of a circular disk propelled by symmetrically distributed camphor pills
Yuki Koyano, Hiroyuki Kitahata, Marian Gryciuk +4
We studied rotation of a disk propelled by a number of camphor pills symmetrically distributed at its edge. The disk was put on a water surface so that it could rotate around a ver…
Rotational motion of a camphor disk in a circular region
Yuki Koyano, Nobuhiko J. Suematsu, Hiroyuki Kitahata
In a two-dimensional axisymmetric system, a symmetric self-propelled particle exhibits rotational or oscillatory motion from the consideration of the system symmetry. In the presen…
Relationship between the size of camphor-driven rotor and its angular velocity
Yuki Koyano, Marian Gryciuk, Paulina Skrobanska +4
We consider a rotor made of two camphor disks glued below the ends of a plastic stripe. The disks are floating on a water surface and the plastic stripe does not touch the surface.…
Oscillatory Motion of a Camphor Grain in a One-Dimensional Finite Region
Yuki Koyano, Tatsunari Sakurai, Hiroyuki Kitahata
The motion of a self-propelled particle is affected by its surroundings, such as boundaries or external fields. In this paper, we investigated the bifurcation of the motion of a ca…
Hydrodynamic collective effects of active proteins in biological membranes
Yuki Koyano, Hiroyuki Kitahata, Alexander S. Mikhailov
Lipid bilayers forming biological membranes are known to behave as viscous 2D fluids on submicrometer scales; usually they contain a large number of active protein inclusions. Rece…
Oscillation of a Rotating Levitated Droplet: Analysis with a Mechanical Model
Hiroyuki Kitahata, Rui Tanaka, Yuki Koyano +7
A droplet of millimeter-to-centimeter scale can exhibit electrostatic levitation, and such levitated droplets can be used for the measurement of the surface tension of the liquids…
General Criteria for Determining Rotation or Oscillation in a Two-dimensional Axisymmetric System
Yuki Koyano, Natsuhiko Yoshinaga, Hiroyuki Kitahata
A self-propelled particle in a two-dimensional axisymmetric system, such as a particle in a central force field or confined in a circular region, may show rotational or oscillatory…