One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development proces...One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles (AUV). In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable. In the current paper an analysis of undulatory, oscillatory and combined fin-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum axe solved with the Finite Volume Method (FWM) by use of the software CFX-10.0. The undulatory and oscillatory fin movements axe modelled with an equation that is implemented within an additional subroutine and joined with the main solver. N carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations axe carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.展开更多
The water environment of swimming fish in nature is always complex which includes various vortices and fluctuations. In order to study the interaction between the fish and its surrounding complex flow, the physical mo...The water environment of swimming fish in nature is always complex which includes various vortices and fluctuations. In order to study the interaction between the fish and its surrounding complex flow, the physical model with a D-section cylinder placed at the front of a flapping foil is employed. The D-section cylinder is used to produce vortices to contact with the foil as well as the vortices shed from the foil. According to the experimental work of Gopalkrishnan et al., there are three interaction modes between vortices shed from the cylinder and the flapping foil, which are expanding wake, destructive interaction and constructive interaction. Here in this article, three of those typical cases are picked up to reproduce the vortices interaction modes with the modified immersed boundary methods and their hydrodynamic performances are studied further. Results show that, for expanding wake mode and destructive interaction mode, the incoming vortices contact with the foil strongly, inducing relative low pressure domains at the leading-edge of the foil and enlarging the thrust of foils. For constructive mode, the foil slalom between the shed vortices from the D-section cylinder do not contact with them obviously and the foil's thrust is only enlarged a little.展开更多
文摘One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles (AUV). In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable. In the current paper an analysis of undulatory, oscillatory and combined fin-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum axe solved with the Finite Volume Method (FWM) by use of the software CFX-10.0. The undulatory and oscillatory fin movements axe modelled with an equation that is implemented within an additional subroutine and joined with the main solver. N carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations axe carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.
基金Project supported by the National Natural Science Foundation of China(Grant No.10872181)the National Key Basic Research Program of China(973 Program,Grant No.2009CB724303)the Fundamental Research Funds for the Central Universities(Grant No.2010QNA4015)
文摘The water environment of swimming fish in nature is always complex which includes various vortices and fluctuations. In order to study the interaction between the fish and its surrounding complex flow, the physical model with a D-section cylinder placed at the front of a flapping foil is employed. The D-section cylinder is used to produce vortices to contact with the foil as well as the vortices shed from the foil. According to the experimental work of Gopalkrishnan et al., there are three interaction modes between vortices shed from the cylinder and the flapping foil, which are expanding wake, destructive interaction and constructive interaction. Here in this article, three of those typical cases are picked up to reproduce the vortices interaction modes with the modified immersed boundary methods and their hydrodynamic performances are studied further. Results show that, for expanding wake mode and destructive interaction mode, the incoming vortices contact with the foil strongly, inducing relative low pressure domains at the leading-edge of the foil and enlarging the thrust of foils. For constructive mode, the foil slalom between the shed vortices from the D-section cylinder do not contact with them obviously and the foil's thrust is only enlarged a little.