Dynamic coupling in sloshing systems with multiple baffles.

具有多个挡板的晃动系统中的动态耦合。

• 批准号: EP/W006545/1
• 负责人: Matthew Turner
• 金额: $ 8.63万
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW006545%2F1
• 关键词: Dynamic; coupling; sloshing; systems; multiple

When you walk with a cup of coffee, the coffee can slosh back and forth in the cup, and in some cases, spill on the floor. The reason this happens is because as the cup moves in our hand that motion imparts a force on the coffee, causing it to move, while the motion of the coffee imparts its own hydrodynamic force on the wall of the cup, causing the cup itself to move. This dynamic sloshing motion, if we don't stop walking to let it damp out or move our arm in a specific manner to nullify the coffee motion, is destabilizing and hence leads to the coffee being spilt. This coupled phenomena does not necessarily have to be undesirable, and in some cases this process can be used to an advantage. Once such case is in tuned liquid dampers (TLDs), which are large containers of fluid attached to springs, which are placed within high-rise buildings. When these buildings oscillate back and forth due to either high winds or an earthquake, the TLD is forced to move back and forth essentially transferring the energy of the moving building into the fluid. Therefore the understanding of such dynamic sloshing problems is of great practical interest.The introduction of rigid baffles to the dynamic sloshing system can be a useful addition, as these baffles (rigid screens or plates) modify the natural frequency of the system, making it possible to tune the system in such a way as to reduce the motion of the fluid carrying vessel, putting more of the system energy into the fluid. This proposal investigates the introduction of porous and non-porous baffles in two simplified dynamic sloshing problems to identify just how these natural frequencies are modified, and whether it can be modified to coincide with an internal resonance of the system. Such resonances are particularly interesting because they are pathways for energy transfer between modes, and hence all the energy of a moving vessel could be transferred to the fluid (and vice versa) at such a resonance.This project aims to construct a novel, fast and efficient numerical scheme to simulate the motion of a coupled sloshing system where rigid impermeable baffles are inserted on the side walls of a rectangular vessel, which is restricted to oscillate in one horizontal space dimension. The scheme is novel because it incorporates conformal mappings from complex analysis to map the unknown position of the fluid surface to a line, along which the solution can be found. Therefore all the information about the baffle positions and shape is contained in the mapping itself. While the determination of this mapping is non-trivial, its existence makes a seeming intractable problem tractable. The second part of this project focuses on the effect of porous baffles on the system natural frequency. We investigate how the system frequency varies as the porosity (amount of fluid which can pass though) of the baffles vary.

当您喝杯咖啡走路时，咖啡可以在杯子中来回闲逛，在某些情况下，咖啡在地板上溢出。之所以发生的原因是，随着杯子在我们的手中移动时，运动会赋予咖啡的力量，导致它移动，而咖啡的运动则在杯子的墙壁上赋予了自己的水动力力量移动。如果我们不停止步行以使其潮湿或以特定的方式移动我们的手臂以使咖啡动作消除，那么这种动态的摇摆动作将不稳定，因此导致咖啡溢出。这种耦合现象不一定是不可取的，在某些情况下，此过程可以用于优势。一旦这种情况是在调谐的液体阻尼器（TLDS）中，它们是附着在弹簧上的大容器，它们放置在高层建筑物中。当这些建筑物由于大风或地震而来回振荡时，TLD被迫来回移动，从本质上将移动建筑物的能量转移到流体中。因此，对这种动态倾斜问题的理解具有很大的实际兴趣。将刚性挡板引入动态荡妇系统可能是有用的补充，因为这些挡板（刚性屏幕或板）会改变系统的固有频率，使其成为可能以减少流体携带容器的运动的方式调整系统，从而将更多的系统能量放入流体中。该提案研究了两个简化的动态倾斜问题中的多孔和非孔挡板的引入，以确定如何修改这些固有频率，以及是否可以对其进行修改以与系统的内部共振相吻合。这种共振特别有趣，因为它们是模式之间能量传递的途径，因此，在这种共振下，可以将移动容器的所有能量转移到流体（反之亦然）中。此项目旨在构建一个新颖，快速，快速，快速，且有效的数值方案，以模拟耦合的荡妇系统的运动，其中将刚性不可渗透的挡板插入矩形容器的侧壁上，该矩形容器仅限于一个水平空间尺寸振荡。该方案之所以新颖，是因为它结合了从复杂分析到绘制流体表面的未知位置到一条线的连形映射，可以在其中找到溶液。因此，有关挡板位置和形状的所有信息都包含在映射本身中。尽管该映射的确定是不平凡的，但它的存在使一个看似棘手的问题可以解决。该项目的第二部分着重于多孔挡板对系统固有频率的影响。我们研究系统频率的变化是挡板的孔隙率（虽然可以通过的流体量）变化。

项目成果

A new physically realisable internal 1:1 resonance in the coupled pendulum-slosh system

耦合摆晃动系统中新的物理可实现的内部 1:1 共振

• DOI: 10.1016/j.euromechflu.2022.12.004
• 发表时间: 2023
• 期刊: European Journal of Mechanics - B/Fluids
• 作者: Alemi Ardakani H

Stability of jets and wakes confined by compliant walls

受柔顺壁限制的射流和尾流的稳定性

• DOI: 10.1103/physrevfluids.8.063901
• 发表时间: 2023
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: Poole R

Dynamic sloshing in a rectangular vessel with porous baffles

• DOI: 10.1007/s10665-024-10333-7
• 发表时间: 2024-02
• 期刊: Journal of Engineering Mathematics
• 影响因子: 1.3
• 作者: M. R. Turner