The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up consid...The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up considering the beam mode and Morison’s nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin’s method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.展开更多
在舰船的结构强度设计中,耦合入水砰击荷载受到很大的重视。采用计算流体动力学-有限元法(computational fluid dynamics-finite element method,CFD-FEM)双向耦合数值方法,研究重力作用下弹性楔形体于不同流场环境下入水时的流固耦合...在舰船的结构强度设计中,耦合入水砰击荷载受到很大的重视。采用计算流体动力学-有限元法(computational fluid dynamics-finite element method,CFD-FEM)双向耦合数值方法,研究重力作用下弹性楔形体于不同流场环境下入水时的流固耦合问题。首先,以静水中楔形体砰击为例,将其仿真结果与试验进行对比验证该耦合方法的准确性;而后,分析了不同入水速度和底部斜升角的弹性楔形体在静水、流和波浪等不同流场环境中入水时所受砰击荷载以及结构响应和流场的变化。结果表明:静水中楔形体入水砰击与模型试验结果相吻合,证明该数值模拟具有可靠性和可行性;均匀流作用下楔形体入水时由于结构物对来流产生壁面反射,导致楔形体附近在靠近来流侧与远离来流侧流速不同从而产生压力差,楔形体底部向来流方向偏移,不同波浪位置下入水时,模型在波浪速度向上的平衡位置,因波浪与楔形体的相对冲击速度增加,所产生的砰击荷载比静水中大,高应力区主要集中在楔形体底部及焊缝位置。研究结果对舰船结构设计以及入水砰击研究提供了指导依据。展开更多
针对声学多普勒剖面流速仪(acoustic Doppler current profilers,简称ADCP)波浪三要素(波向、波高和波周期)计量校准技术难题,提出了造波水槽和水下实验平台的计量检测方法。首先,设计波向、波高和波周期计量标准器;然后,以美国TRDI公司...针对声学多普勒剖面流速仪(acoustic Doppler current profilers,简称ADCP)波浪三要素(波向、波高和波周期)计量校准技术难题,提出了造波水槽和水下实验平台的计量检测方法。首先,设计波向、波高和波周期计量标准器;然后,以美国TRDI公司V20型和挪威Nortek仪器为例,开展ADCP波浪参数水动力环境计量校准实验研究。实验结果表明,波高、波周期和波向数据最大示值误差分别为-0.09 m,0.6 s和4°,满足国家相关技术标准要求。波高扩展不确定度为0.04 m,依据计量学理论,认为本校准方法可行。本研究成果对ADCP波浪参数计量校准工作具有一定指导意义。展开更多
基金Project supported by the National Natural Science Foundation of China (No.50279026) andthe National985Engineering Project in China
文摘The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up considering the beam mode and Morison’s nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin’s method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.
文摘在舰船的结构强度设计中,耦合入水砰击荷载受到很大的重视。采用计算流体动力学-有限元法(computational fluid dynamics-finite element method,CFD-FEM)双向耦合数值方法,研究重力作用下弹性楔形体于不同流场环境下入水时的流固耦合问题。首先,以静水中楔形体砰击为例,将其仿真结果与试验进行对比验证该耦合方法的准确性;而后,分析了不同入水速度和底部斜升角的弹性楔形体在静水、流和波浪等不同流场环境中入水时所受砰击荷载以及结构响应和流场的变化。结果表明:静水中楔形体入水砰击与模型试验结果相吻合,证明该数值模拟具有可靠性和可行性;均匀流作用下楔形体入水时由于结构物对来流产生壁面反射,导致楔形体附近在靠近来流侧与远离来流侧流速不同从而产生压力差,楔形体底部向来流方向偏移,不同波浪位置下入水时,模型在波浪速度向上的平衡位置,因波浪与楔形体的相对冲击速度增加,所产生的砰击荷载比静水中大,高应力区主要集中在楔形体底部及焊缝位置。研究结果对舰船结构设计以及入水砰击研究提供了指导依据。
