The turbulent cavitating flow around the propelling pump tip clearance is numerically simulated using the large eddy simulation(LES)method coupled with the Zwart-Gerber-Belamri(ZGB)cavitation model to investigate the ...The turbulent cavitating flow around the propelling pump tip clearance is numerically simulated using the large eddy simulation(LES)method coupled with the Zwart-Gerber-Belamri(ZGB)cavitation model to investigate the cavitation-vortex interaction mechanism.The calculated cavitation structures around the blades are in a remarkable agreement with the experimental results.The distributions of the tip clearance vortex under two cavitation conditions are obtained and compared.The results show that the cavitation development enhances the vorticity generation and the flow unsteadiness around the tip clearance of a propelling pump.Vortices are basically located around the cavitation areas,particularly in the tip clearance region,during the cavitation.The relative vorticity transport equation is applied for the cavitating turbulent flows and it is further indicated that the vortex stretching term makes the main contribution in the vortex production,and the baroclinic torque and dilation terms are important source terms for the vorticity generation in the cavitating flow.In addition,the viscous diffusion term and the Coriolis force term are significant in modifying the vorticity field inside the blade tip clearance.展开更多
With the development of camera technology,high-speed cameras have greatly contributed to capturing the movement and posture of animals,which has dramatically promoted experimental biology research.At the same time,wit...With the development of camera technology,high-speed cameras have greatly contributed to capturing the movement and posture of animals,which has dramatically promoted experimental biology research.At the same time,with the concept of bionics gradually gaining popularity among researchers,the design of robots is absorbing more and more biological features,where the interest in the bio-inspired robot is hewed out.Compared with the traditional robot,the bio-inspired robot imitates the motion pattern to achieve similar propulsion features,which may be more effective and reasonable.In this paper,the motion patterns of aquatic animals are divided into four categories according to their propulsion mechanisms:drag-based,lift-based,jet-based,and interface-based.And bio-inspired robots imitating aquatic prototypes are introduced and reviewed.Finally,the prospect of aquatic bio-inspired robots is discussed.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51822903,11772239).
文摘The turbulent cavitating flow around the propelling pump tip clearance is numerically simulated using the large eddy simulation(LES)method coupled with the Zwart-Gerber-Belamri(ZGB)cavitation model to investigate the cavitation-vortex interaction mechanism.The calculated cavitation structures around the blades are in a remarkable agreement with the experimental results.The distributions of the tip clearance vortex under two cavitation conditions are obtained and compared.The results show that the cavitation development enhances the vorticity generation and the flow unsteadiness around the tip clearance of a propelling pump.Vortices are basically located around the cavitation areas,particularly in the tip clearance region,during the cavitation.The relative vorticity transport equation is applied for the cavitating turbulent flows and it is further indicated that the vortex stretching term makes the main contribution in the vortex production,and the baroclinic torque and dilation terms are important source terms for the vorticity generation in the cavitating flow.In addition,the viscous diffusion term and the Coriolis force term are significant in modifying the vorticity field inside the blade tip clearance.
基金This work was supported by National Natural Science Foundation of China(62273042,61773064,61503028).
文摘With the development of camera technology,high-speed cameras have greatly contributed to capturing the movement and posture of animals,which has dramatically promoted experimental biology research.At the same time,with the concept of bionics gradually gaining popularity among researchers,the design of robots is absorbing more and more biological features,where the interest in the bio-inspired robot is hewed out.Compared with the traditional robot,the bio-inspired robot imitates the motion pattern to achieve similar propulsion features,which may be more effective and reasonable.In this paper,the motion patterns of aquatic animals are divided into four categories according to their propulsion mechanisms:drag-based,lift-based,jet-based,and interface-based.And bio-inspired robots imitating aquatic prototypes are introduced and reviewed.Finally,the prospect of aquatic bio-inspired robots is discussed.
