An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppre...An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppression device was designed in which the jet pipe was horizontally fixed to the front end of the riser.By varying three different excitation spacings and multi-stage outflow velocities,the influence law of the dominant frequency,dimensionless displacement and other dynamic response parameters was studied under different excitation spacings,and the mechanism and sensitive characteristics of the disturbance suppression were explored.The results indicate that the variation of excitation spacing makes gas curtain enter the strong disturbed flow region at different velocities and angles,and the coupling relationship between excitation spacing and reduced velocity is the key factor to enter the strong disturbed flow region to achieve the optimal disturbance suppression.In the strong disturbed flow region,the influence of gas curtain on the dominant frequency is obviously affected by the flow velocity,while the vibration displacement is stable at the same amplitude and is weakly affected by the flow velocity.Gas curtain can effectively disturb the formation of vortex shedding,destroy the strong nonlinear coupled vibration of the riser,and achieve better vibration suppression effect.In the weak disturbed flow region,the vortex length of the riser tail is prolonged,the strong nonlinear coupled vibration of the riser is gradually restored,and the vibration suppression effect of the device gradually decreases.展开更多
A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independ...A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independent disturbances. A ground wave polarimetric radar with the ability of radio disturbance suppresion is then introduced. Some numerical results demonstrate the effectiveness of single sample polarization filtering method for ground wave polarimetric radar.展开更多
A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d a...A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.展开更多
基金This work was supported by National Natural Science Foundation of China(Grant No.51709161)the Key Research and Development Program of Shandong Province(Grant Nos.2019GHY112061 and 2018GHY115045)+2 种基金Research and Innovation Team of Ocean Oil and Gas Development Engineering Structure,College of Civil Engineering and Architecture,Shandong University of Science and Technology(Grant No.2019TJKYTD01)Shandong Provincial Natural Science Foundation,China(Grant No.ZR2017BEE041)Science and technology innovation project for postgraduates of Shandong University of Science and Technology(Grant No.SDKDYC180327).
文摘An experimental investigation on the disturbance effect of jet-type active vibration suppression device on vortexinduced vibration of deep-sea riser was carried out in the wave-flow combined flume.The vibration suppression device was designed in which the jet pipe was horizontally fixed to the front end of the riser.By varying three different excitation spacings and multi-stage outflow velocities,the influence law of the dominant frequency,dimensionless displacement and other dynamic response parameters was studied under different excitation spacings,and the mechanism and sensitive characteristics of the disturbance suppression were explored.The results indicate that the variation of excitation spacing makes gas curtain enter the strong disturbed flow region at different velocities and angles,and the coupling relationship between excitation spacing and reduced velocity is the key factor to enter the strong disturbed flow region to achieve the optimal disturbance suppression.In the strong disturbed flow region,the influence of gas curtain on the dominant frequency is obviously affected by the flow velocity,while the vibration displacement is stable at the same amplitude and is weakly affected by the flow velocity.Gas curtain can effectively disturb the formation of vortex shedding,destroy the strong nonlinear coupled vibration of the riser,and achieve better vibration suppression effect.In the weak disturbed flow region,the vortex length of the riser tail is prolonged,the strong nonlinear coupled vibration of the riser is gradually restored,and the vibration suppression effect of the device gradually decreases.
文摘A new method of single sample polarization filtering is proposed. The algorithm is fast and suitable for the polarization processing of stationary or nonstationary polarized disturbed signals with one or more independent disturbances. A ground wave polarimetric radar with the ability of radio disturbance suppresion is then introduced. Some numerical results demonstrate the effectiveness of single sample polarization filtering method for ground wave polarimetric radar.
基金Supported by the National Science Fund for Distinguished Young Scholars under Grant 52025073 and the Zhenjiang Key Research Program under Grant GY2020011.
文摘A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.
