The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the nmlti-motion modes of the autonomous underwater vehicle （AUV） such as vectored thruster and wheele...The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the nmlti-motion modes of the autonomous underwater vehicle （AUV） such as vectored thruster and wheeled movement. In order to study the interactional principle between the hull and the wheel propellers while the AUV navigating in water, the computational fluid dynamics （CFD） method is used to simulate numerically the unsteady viscous flow around AUV with propellers by using the Reynolds-averaged Navier-Stokes （RANS） equations, shear-stress transport （SST） k-w model and pressure with splitting of operators （PISO） algorithm based on sliding mesh. The hydrodynamic parameters of AUV with propellers such as resistance, pressure and velocity are got, which reflect well the real ambient flow field of AUV with propellers. Then, the semi-implicit method for pressure-linked equations （SIMPLE） algorithm is used to compute the steady viscous flow field of AUV hull and propellers, respectively. The computational results agree well with the experimental data, which shows that the numerical method has good accuracy in the prediction of hydrodynamic performance. The interaction between AUV hull and wheel propellers is predicted qualitatively and quantitatively by comparing the hydrodynamic parameters such as resistance, pressure and velocity with those from integral computation and partial computation of the viscous flow around AUV with propellers, which provides an effective reference to the shady on noise and vibration of AUV hull and propellers in real environment. It also provides technical support for the design of new AUVs.展开更多
With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow c...With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow characteristics of compressible flow through micro-channels and micronozzles.An improved surface roughness viscosity model is used to simulate the effect of surface roughness on micro-channels flow characteristics.Using this model,better agreements between the computational results and the experimental data are found.The result indicates that the surface roughness is one of the important factors affecting the flow characteristics of gas through micro-channels.The numerical investigation on the expansion channel shows that by using the laminar model that considers surface roughness,the computational results and experimental data are consistent when Re<450,whereas deviation increases when Re>450.Based on the synthetic model with considerations of turbulence viscosity and surface roughness,the numerical results and the experimental data are identical.展开更多
基金Project(2006AA09Z235) supported by National High Technology Research and Development Program of ChinaProject(CX2009B003) supported by Hunan Provincial Innovation Foundation For Postgraduate,China
文摘The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the nmlti-motion modes of the autonomous underwater vehicle （AUV） such as vectored thruster and wheeled movement. In order to study the interactional principle between the hull and the wheel propellers while the AUV navigating in water, the computational fluid dynamics （CFD） method is used to simulate numerically the unsteady viscous flow around AUV with propellers by using the Reynolds-averaged Navier-Stokes （RANS） equations, shear-stress transport （SST） k-w model and pressure with splitting of operators （PISO） algorithm based on sliding mesh. The hydrodynamic parameters of AUV with propellers such as resistance, pressure and velocity are got, which reflect well the real ambient flow field of AUV with propellers. Then, the semi-implicit method for pressure-linked equations （SIMPLE） algorithm is used to compute the steady viscous flow field of AUV hull and propellers, respectively. The computational results agree well with the experimental data, which shows that the numerical method has good accuracy in the prediction of hydrodynamic performance. The interaction between AUV hull and wheel propellers is predicted qualitatively and quantitatively by comparing the hydrodynamic parameters such as resistance, pressure and velocity with those from integral computation and partial computation of the viscous flow around AUV with propellers, which provides an effective reference to the shady on noise and vibration of AUV hull and propellers in real environment. It also provides technical support for the design of new AUVs.
基金supported by the National Natural Science Foundation of China(Grant No. 10872106)
文摘With the development of the micro-electro-mechanical system (MEMS),the flow characteristics in micro-channels have drawn increasing attention.In this paper,numerical simulations are conducted to investigate the flow characteristics of compressible flow through micro-channels and micronozzles.An improved surface roughness viscosity model is used to simulate the effect of surface roughness on micro-channels flow characteristics.Using this model,better agreements between the computational results and the experimental data are found.The result indicates that the surface roughness is one of the important factors affecting the flow characteristics of gas through micro-channels.The numerical investigation on the expansion channel shows that by using the laminar model that considers surface roughness,the computational results and experimental data are consistent when Re<450,whereas deviation increases when Re>450.Based on the synthetic model with considerations of turbulence viscosity and surface roughness,the numerical results and the experimental data are identical.
