In consideration of the problem that the effect of conduit structure on water hammer has been ignored in the classical theory,the Poisson coupling between the fluid and the pipeline was studied and a fourteen-equation...In consideration of the problem that the effect of conduit structure on water hammer has been ignored in the classical theory,the Poisson coupling between the fluid and the pipeline was studied and a fourteen-equation mathematical model of fluid-structure interaction(FSI)was developed.Then,the transfer matrix method(TMM)was used to calculate the modal frequency,modal shape and frequency response.The results were compared with that in experiment to verify the correctness of the TMM and the results show that the fluid-structure coupling has a greater impact on the modal frequencies than the modal shape.Finally,the influence on the response spectrum of different damping ratios was studied and the results show that the natural frequency under different damping ratios has changed little but there is a big difference for the pressure spectrum.With the decreasing of damping ratio,the damping of the system on frequency spectrum is more and more significant and the dispersion and dissipation is more and more apparent.Therefore the appropriate damping ratio should be selected to minimize the effects of the vibration of the FSI.The results provide references for the theory research of FSI in the transient process.展开更多
随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探...随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探讨了该领域的研究现状,将Web of Science核心数据集的科学引文索引和Scopus数据库中汽车多模态交互的相关文献作为研究对象,利用CiteSpace文献计量工具对其进行图谱可视化分析,对该领域的发展历程和现状进行脉络梳理,探析研究热点及方向,并对未来研究趋势进行预测。展开更多
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc...To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.展开更多
The conventional honey production is dominated by fragmented,small-scale individual farming models.The traditional approach of honey-harvesting involving manual beehive frames extraction,beeswax layer excision and cen...The conventional honey production is dominated by fragmented,small-scale individual farming models.The traditional approach of honey-harvesting involving manual beehive frames extraction,beeswax layer excision and centrifugal honey separation,expose beekeepers to potential bee stings and frequently compromise honeycomb integrity.To address these limitations,we designed an automated honey-harvesting robot capable of autonomous frame extraction and beeswax removal.The robot mainly consists of a mobile mechanism equipped with image recognition for beehive localization,a magnetic adsorption-based beehive frame handling device(60.8 N maximum suction)coupled with a cross-slide mechanism for precise frame manipulation,and a thermal beeswax layer-melting apparatus,with optimal melting parameters(15 m/s airflow at 90℃ for 30 seconds)determined through rigorous thermal flow simulations utilizing FLUENT/Mechanical software.Field experiments demonstrated beehive frames handling success rate exceeding 85%,beeswax layer removal efficacy over 80% and damage of honeycombs below 30%.The experiment results validate the robot's operational reliability and its capacity to automate critical harvesting procedures.This study significantly reduces the labor intensity for beekeepers,effectively eliminates the risk of direct human-bee contact and improves the removal of beeswax layer,thereby catalyzing the modernization of the beekeeping industry.展开更多
文摘In consideration of the problem that the effect of conduit structure on water hammer has been ignored in the classical theory,the Poisson coupling between the fluid and the pipeline was studied and a fourteen-equation mathematical model of fluid-structure interaction(FSI)was developed.Then,the transfer matrix method(TMM)was used to calculate the modal frequency,modal shape and frequency response.The results were compared with that in experiment to verify the correctness of the TMM and the results show that the fluid-structure coupling has a greater impact on the modal frequencies than the modal shape.Finally,the influence on the response spectrum of different damping ratios was studied and the results show that the natural frequency under different damping ratios has changed little but there is a big difference for the pressure spectrum.With the decreasing of damping ratio,the damping of the system on frequency spectrum is more and more significant and the dispersion and dissipation is more and more apparent.Therefore the appropriate damping ratio should be selected to minimize the effects of the vibration of the FSI.The results provide references for the theory research of FSI in the transient process.
文摘随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探讨了该领域的研究现状,将Web of Science核心数据集的科学引文索引和Scopus数据库中汽车多模态交互的相关文献作为研究对象,利用CiteSpace文献计量工具对其进行图谱可视化分析,对该领域的发展历程和现状进行脉络梳理,探析研究热点及方向,并对未来研究趋势进行预测。
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_0714).
文摘To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.
基金National Natural Science Foundation of China(31700644)Shandong Province Postdoctoral Innovation Project(SDCX-ZG-202400195)。
文摘The conventional honey production is dominated by fragmented,small-scale individual farming models.The traditional approach of honey-harvesting involving manual beehive frames extraction,beeswax layer excision and centrifugal honey separation,expose beekeepers to potential bee stings and frequently compromise honeycomb integrity.To address these limitations,we designed an automated honey-harvesting robot capable of autonomous frame extraction and beeswax removal.The robot mainly consists of a mobile mechanism equipped with image recognition for beehive localization,a magnetic adsorption-based beehive frame handling device(60.8 N maximum suction)coupled with a cross-slide mechanism for precise frame manipulation,and a thermal beeswax layer-melting apparatus,with optimal melting parameters(15 m/s airflow at 90℃ for 30 seconds)determined through rigorous thermal flow simulations utilizing FLUENT/Mechanical software.Field experiments demonstrated beehive frames handling success rate exceeding 85%,beeswax layer removal efficacy over 80% and damage of honeycombs below 30%.The experiment results validate the robot's operational reliability and its capacity to automate critical harvesting procedures.This study significantly reduces the labor intensity for beekeepers,effectively eliminates the risk of direct human-bee contact and improves the removal of beeswax layer,thereby catalyzing the modernization of the beekeeping industry.
