A series of numerical sinmlations about a small scale （aspect ratio： 63.2） flexible pipe undergoing forced harmonious oscillation and vortex-induced vibration （VIV） have been taken into account. The wake hydrodyn...A series of numerical sinmlations about a small scale （aspect ratio： 63.2） flexible pipe undergoing forced harmonious oscillation and vortex-induced vibration （VIV） have been taken into account. The wake hydrodynamics and pipe deformation were accomplished by ANSYS MFX solution strat- egy designed for fluid-structure interaction （FSI） problem with well-performed LES model. The configuration of structured mesh, multi-domain design, different mesh stiffness admeasured by User Fortran ensured that the numerical task was competent to deal with large deformation related to this case. The introduction of instantaneous amplitude definition and modeless component decom- position method （Chen and Kim, 2008） was helpful to reveal much more information from modal analysis. Most results from numerical simulation are generally consistent with those from model test （Choi and Hong, 2000） via the comparison between them. As supplementary to model test, visualization of the vortex wake was also provided. It has been proved that the forced oscillation doesn＇t only excite a complicated dumbbell-like wake pattern around the outer thimble, but also results in inner flow inside the PVC pipe. The velocity of the inner flow increases with the frequency of forced oscillation.展开更多
A though China has seen a large trade surplus in the Apast few years,it is striking that the large trade surplus has not been accompanied by large selling of foreign exchange(FX)on China's foreign exchange market....A though China has seen a large trade surplus in the Apast few years,it is striking that the large trade surplus has not been accompanied by large selling of foreign exchange(FX)on China's foreign exchange market.While this has prompted many market participants to talk about potential"FX hoarding,"it has not resulted in a significant increase in official FX reserves or private sector FX deposits.In fact,private sector FX deposits dropped for the most of the past few years.Is this MFX hoarding"or MFX dishoarding"?展开更多
基金Korea Research Foundation Grant funded by the Korean Government (MOEHRD,Basic Research Promotion Fund) (KRF-2008-D00556)Mokpo National University RIC for Midisize Shipbuilding
文摘A series of numerical sinmlations about a small scale （aspect ratio： 63.2） flexible pipe undergoing forced harmonious oscillation and vortex-induced vibration （VIV） have been taken into account. The wake hydrodynamics and pipe deformation were accomplished by ANSYS MFX solution strat- egy designed for fluid-structure interaction （FSI） problem with well-performed LES model. The configuration of structured mesh, multi-domain design, different mesh stiffness admeasured by User Fortran ensured that the numerical task was competent to deal with large deformation related to this case. The introduction of instantaneous amplitude definition and modeless component decom- position method （Chen and Kim, 2008） was helpful to reveal much more information from modal analysis. Most results from numerical simulation are generally consistent with those from model test （Choi and Hong, 2000） via the comparison between them. As supplementary to model test, visualization of the vortex wake was also provided. It has been proved that the forced oscillation doesn＇t only excite a complicated dumbbell-like wake pattern around the outer thimble, but also results in inner flow inside the PVC pipe. The velocity of the inner flow increases with the frequency of forced oscillation.
文摘A though China has seen a large trade surplus in the Apast few years,it is striking that the large trade surplus has not been accompanied by large selling of foreign exchange(FX)on China's foreign exchange market.While this has prompted many market participants to talk about potential"FX hoarding,"it has not resulted in a significant increase in official FX reserves or private sector FX deposits.In fact,private sector FX deposits dropped for the most of the past few years.Is this MFX hoarding"or MFX dishoarding"?
