Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and t...Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and the physical model.The effect of the viscosity ratio between the droplet and the solvent and the effect of the confinement are systematically investigated.The droplet is in an off-centerline equilibrium position with a specific selection of the parameters.A large viscosity ratio makes the droplet locate in a near-wall equilibrium position,and a large capillary number makes the droplet migrate to the near-centerline region of the channel.For the droplet migration at the same Capillary number,there is a critical width of the channel,which is less than twice of the droplet diameter,and the droplet will only migrate to the channel centerline if the width is less than this critical value.展开更多
To develop a bionic maneuverable propulsion system to be applied in a small underwater vehicle, a new conceptual design of the bionic propulsion is applied to the traditional underwater glider. The numerical simulatio...To develop a bionic maneuverable propulsion system to be applied in a small underwater vehicle, a new conceptual design of the bionic propulsion is applied to the traditional underwater glider. The numerical simulation focuses on the autonomous under- water glider （AUG）＇s flapping propulsion at Re = 200 by solving the incompressible viscous Navier-Stokes equations coupled with the immersed boundary method. The systematic analysis of the effect of different motion parameters on the propulsive efficie- ncy of the AUG is carried out, including the hydrofoil＇s heaving amplitude, the pitching amplitude, the phase lag between heaving and pitching and the flapping frequency. The results obtained in this study can provide some physical insights into the propulsive mechanisms in the flapping -based locomotion.展开更多
基金supported by the National Natural Science Foun-dations of China(Grant Nos.11402230,11332009 and 11272284)
文摘Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and the physical model.The effect of the viscosity ratio between the droplet and the solvent and the effect of the confinement are systematically investigated.The droplet is in an off-centerline equilibrium position with a specific selection of the parameters.A large viscosity ratio makes the droplet locate in a near-wall equilibrium position,and a large capillary number makes the droplet migrate to the near-centerline region of the channel.For the droplet migration at the same Capillary number,there is a critical width of the channel,which is less than twice of the droplet diameter,and the droplet will only migrate to the channel centerline if the width is less than this critical value.
基金Project supported by the National Natural Science Foun-dation of China(Grant No.51279184)
文摘To develop a bionic maneuverable propulsion system to be applied in a small underwater vehicle, a new conceptual design of the bionic propulsion is applied to the traditional underwater glider. The numerical simulation focuses on the autonomous under- water glider （AUG）＇s flapping propulsion at Re = 200 by solving the incompressible viscous Navier-Stokes equations coupled with the immersed boundary method. The systematic analysis of the effect of different motion parameters on the propulsive efficie- ncy of the AUG is carried out, including the hydrofoil＇s heaving amplitude, the pitching amplitude, the phase lag between heaving and pitching and the flapping frequency. The results obtained in this study can provide some physical insights into the propulsive mechanisms in the flapping -based locomotion.
