One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a ...One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a unique bidirectional asymmetrical jet system.Using observed hydrology and historical charts,the ECOMSED model was applied in morphodynamic analysis of the dynamic structures and dynamic equilibrium of the Yamen jet system and its effect on sedimentation.It was found that (1) the nonlinear interaction of Yamen dynamic structures could not be ignored,as while the Coriolis force and friction force were generally of the same order of magnitude,the effect of friction force was greater;(2) the bidirectional asymmetrical jet system was flood preferential flow to the north of the channel mouth and ebb preferential flow to the south;and (3) the bidirectional asymmetrical jet system was the dominant factor in the long term stability of the Yamen deep trough.展开更多
Linear rolling guideways(LRGs) play an important role in precision engineering. In the pre-rolling region, the hysteretic friction force exerts great impacts on the positioning accuracy. Numerical and experimental stu...Linear rolling guideways(LRGs) play an important role in precision engineering. In the pre-rolling region, the hysteretic friction force exerts great impacts on the positioning accuracy. Numerical and experimental studies of the hysteresis of friction force are presented in this paper. A model, which is based on the stripe theory and the simplified theory of rolling contact, is built to describe the transient hysteresis of the friction force. Then, the model is modified by taking the anelasticity effect into consideration. Experimentally, a linear motor direct-drive setup is utilized to measure the transient asymmetrical hysteresis of the friction force in the pre-rolling region of an LRG. The influences of the pre-rolling displacement and the dwelling time on the asymmetrical hysteresis of the friction force are studied. The numerical and experimental results are well correlated, which shows good accuracy of the model. The transient asymmetrical hysteresis of friction force in the pre-rolling region of LRGs can thus be determined using the model.展开更多
基金supported by Guangdong Natural Science Foundation (Grant No. 9151027501000111)‘908’ Marine Survey Project (Grant No. 908-02-01-04)National Natural Science Foundation of China (Grant No. 50839005)
文摘One of eight gates of the Pearl River Estuary,the Yamen Inlet is a bedrock channel mouth connecting the Huangmao Sea and Yamen Channel.The wider water surfaces of the upper and lower reaches of the entrance produce a unique bidirectional asymmetrical jet system.Using observed hydrology and historical charts,the ECOMSED model was applied in morphodynamic analysis of the dynamic structures and dynamic equilibrium of the Yamen jet system and its effect on sedimentation.It was found that (1) the nonlinear interaction of Yamen dynamic structures could not be ignored,as while the Coriolis force and friction force were generally of the same order of magnitude,the effect of friction force was greater;(2) the bidirectional asymmetrical jet system was flood preferential flow to the north of the channel mouth and ebb preferential flow to the south;and (3) the bidirectional asymmetrical jet system was the dominant factor in the long term stability of the Yamen deep trough.
文摘Linear rolling guideways(LRGs) play an important role in precision engineering. In the pre-rolling region, the hysteretic friction force exerts great impacts on the positioning accuracy. Numerical and experimental studies of the hysteresis of friction force are presented in this paper. A model, which is based on the stripe theory and the simplified theory of rolling contact, is built to describe the transient hysteresis of the friction force. Then, the model is modified by taking the anelasticity effect into consideration. Experimentally, a linear motor direct-drive setup is utilized to measure the transient asymmetrical hysteresis of the friction force in the pre-rolling region of an LRG. The influences of the pre-rolling displacement and the dwelling time on the asymmetrical hysteresis of the friction force are studied. The numerical and experimental results are well correlated, which shows good accuracy of the model. The transient asymmetrical hysteresis of friction force in the pre-rolling region of LRGs can thus be determined using the model.
