Flow-induced vibrations and instabilities of structures

本研究的长期目标是：（i）获得完整的物理理解的动态行为和（ii）生成适当的预测理论模型，并通过实验验证它们的流致振动/不稳定性的圆柱形结构与内部和/或外部轴向流。 短期目标如下[括号内为应用]。 1. 通过线性和非线性分析/CFD模型和实验[海洋采矿、液化天然气生产、碳氢化合物储存、甲烷水合物开采]，研究悬臂管和圆柱形壳体在其自由端排放或吸入流体的动力学，流体的密度和流速沿着其长度变化，同时在其外部受到受限轴向流的影响。 2. 探索新的流路策略，以利用流致激励和阻尼对流速和流向的依赖性，以延迟/防止颤振[上文§1中的应用]或产生近零阻尼[低阻尼MEMS/纳米器件]。 3. 使用几何/材料周期性的连续性和功能梯度材料来生产被动和主动管段，用于插入管道中，以破坏波的传播并减少声音的传播[过滤液压系统中的噪音]。 4. 通过分析/CFD建模和实验[热交换器、核反应堆、海上石油/天然气勘探和生产]，研究轴向流中横向约束圆柱支柱和拖曳圆柱体的非线性动力学。 所有这些工作都可能立即对加拿大石油和天然气、航空和发电工业以及对这些领域的HQP培训有用。

The long-term objectives of this research on flow-induced vibrations/instabilities of cylindrical structures with internal and/or external axial flow are: (i) to gain full physical understanding of the dynamical behaviour and (ii) to generate appropriate predictive theoretical models and validate them experimentally. The short-term objectives are as follows [with applications in brackets]. 1. The dynamics of cantilevered pipes and cylindrical shells discharging or aspirating fluid at their free end, with variable density and flow velocity along their length, and simultaneously subjected to confined axial flow on their exterior, via linear and nonlinear analytical/CFD models and experiments [ocean mining, LNG production, hydrocarbon storage, methane hydrate exploitation]. 2. The exploration of novel flow-path strategies to exploit the dependence of flow-induced excitation and damping on flow velocity and flow direction, either to delay/prevent flutter [applications in §1 above] or to produce near-zero damping [low-damping MEMS/nano devices]. 3. The use of geometric/material periodic idscontinuities and functionally graded materials to produce passive and active pipe segments, for insertion in pipelines in order to disrupt wave propagation and diminish sound transmission [filtering noise in hydraulic systems]. 4. The nonlinear dynamics of transversally confined cylindrical struts in axial flow and of towed cylinders, via analytical/CFD modelling and experiments [heat exchangers, nuclear reactors, offshore oil/gas exploration and production]. All of this work is potentially immediately useful to the Canadian oil-and-gas, aeronautical and power- generation industries and for training HQP in these fields.