FROTH: Fundamentals and Reliability of Offshore Structure Hydrodynamics

FROTH：海上结构流体动力学的基础知识和可靠性

• 批准号: EP/J012866/1
• 负责人: Deborah Greaves
• 金额: $ 55.57万
• 依托单位: Plymouth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ012866%2F1
• 关键词: FROTH; Fundamentals; Reliability; Offshore; Structure

The FROTH project is a close collaboration between five universities with significant experience in research into wave interactions with fixed and floating structures working together to combine and apply their expertise to different aspects of the problem. The aim is to investigate the detailed physics of violent hydrodynamic impact loading on rigid and elastic structures through a carefully integrated programme of numerical modelling and physical experiments at large scale. Open source numerical code will be developed to simulate laboratory experiments to be carried out in the new national wave and current facility at the UoP [http://www.plymouth.ac.uk/pages/view.asp?page=34369]. It is well known that climate change will lead to sea level rise and increased storm activity (either more severe individual storms or more storms overall, or both) in the offshore marine environment around the UK and north-western Europe. This has critical implications for the safety of personnel on existing offshore structures and for the safe operation of existing and new classes of LNG carrier vessels whose structures are subject to large instantaneous loadings due to violent sloshing of transported liquids in severe seas. Some existing oil and gas offshore structures in UK waters are already up to 40 years old and these aging structures need to be re-assessed to ensure that they can withstand increased loading due to climate change, and to confirm that their life can be extended into the next 25 years. The cost of upgrading these existing structures and of ensuring the survivability and safe operation of new structures and vessels will depend critically on the reliability of hydrodynamic impact load predictions. These loadings cause severe damage to sea walls, tanks providing containment to sloshing liquids (such as in LNG carriers) and damage to FPSOs and other offshore marine floating structures such as wave energy converters.Whilst the hydrodynamics in the bulk of a fluid is relatively well understood, the violent motion and break-up of the water surface remains a major challenge to simulate with sufficient accuracy for engineering design. Although free surface elevations and average loadings are often predicted relatively well by analysis techniques, observed instantaneous peak pressures are not reliably predicted in such extreme conditions and are often not repeatable even in carefully controlled laboratory experiments. There remain a number of deeply fundamental open questions as to the detailed physics of hydrodynamic impact loading, even for fixed structures and the extremely high-pressure impulse that may occur. In particular, uncertainty exists in the understanding of the influence of: the presence of air in the water (both entrapped pockets and entrained bubbles) as the acoustic properties of the water change leading to variability of wave impact pressures measured in experiments; flexibility of the structure leading to hydroelastic response; steepness and three dimensionality of the incident wave.This proposal seeks to directly attack this fundamentally difficult and safety-critical problem with a tightly integrated set of laboratory experiments and state of the art numerical simulations with the ultimate aim of providing improved guidance to the designers of offshore, marine and coastal structures, both fixed and floating.

泡沫项目是五个大学之间的密切合作，在研究与固定和浮动结构之间的波浪相互作用方面具有丰富的研究经验，共同将其专业知识合并到问题的各个方面。目的是通过大规模的数值建模和物理实验的精心整合的程序来研究剧烈的流体动力撞击负荷对刚性和弹性结构的详细物理。将开发开源数值代码，以模拟在UOP的新国家浪潮和当前设施中进行的实验室实验[http://www.plymouth.ac.ac.uk/pages/pages/view.asp?page?page=34369]。众所周知，在英国和西北欧洲的海上海洋环境中，气候变化将导致海平面上升并增加风暴活动（无论是更严重的单个风暴还是更多的风暴或更多风暴，或两者兼而有之）。这对人员对现有离岸结构的安全以及现有和新类别的液化天然气载波船的安全操作具有至关重要的意义，这些液化天然气载体容器的结构由于在严重海洋中运输的液体的猛烈散布而受到大量瞬时载荷。英国水域中一些现有的石油和天然气建筑物已经有40年的历史了，这些老化结构需要进行重新评估，以确保它们能够承受由于气候变化而承受的增加，并确认它们的寿命可以延长到未来25年。升级这些现有结构的成本以及确保新结构和船只的生存能力和安全运行的成本将取决于水动力撞击负荷预测的可靠性。这些负荷对海墙造成严重破坏，为宽宽液体（例如在LNG载体中）提供遏制，以及对FPSOS和其他海上海洋浮动结构（例如波浪能转化器）的损坏。当液体的整体中流体动力学相对良好地理解，可以很好地理解水面的挑战，并且可以使水面的挑战足以使水表面的挑战能够仿效，并且可以使工程变得有效。尽管通常通过分析技术可以很好地预测自由表面升高和平均负载，但是在这种极端条件下观察到的瞬时峰值压力并不能可靠地预测，即使在经过精心控制的实验室实验中，通常也无法重复。关于固定结构以及可能发生的极高的压力冲动，关于流体动力撞击负荷的详细物理，仍然存在许多深刻的开放问题。特别是，对：水中的空气存在（夹杂的口袋和被夹带的气泡）的影响是不确定性的，因为水变化的声学特性导致实验中测得的波浪撞击压力的可变性；导致水力弹性反应的结构的灵活性；事件波的陡峭度和三个维度。该提案试图通过一组紧密整合的实验室实验和最先进的数值模拟来直接攻击这一根本困难和关键问题的问题，其最终目的是为海上，海洋和沿海结构的设计师提供改进的指导，包括固定和固定。

项目成果

Harmonic structure of the nonlinear force on a fixed ship-shaped floating production, storage and offloading vessel under dispersive phase-focused wave groups

• DOI: 10.1063/5.0141342
• 发表时间: 2023-04
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Hao Chen;L. Qian;Deping Cao

Simulation of breaking wave impact on a vertical wall with a compressible two-phase flow model

用可压缩两相流模型模拟破碎波对垂直壁的冲击

• 发表时间: 2015
• 作者: Gao F.

Numerical wave tank study of extreme waves and wave-structure interaction using OpenFoam®

• DOI: 10.1016/j.oceaneng.2016.09.017
• 发表时间: 2016-11
• 期刊: Ocean Engineering
• 影响因子: 5
• 作者: Zhengjun Hu;D. Greaves;A. Raby

Oblique focused wave group generation and interaction with a fixed FPSO-shaped body: 3D CFD simulations and comparison with experiments

• DOI: 10.1016/j.oceaneng.2019.106524
• 发表时间: 2019-11
• 期刊: Ocean Engineering
• 影响因子: 5
• 作者: Hao Chen;L. Qian;W. Bai;Zhihua Ma;Zaibin Lin;Mi-An Xue

Numerical Simulation of Breaking Wave Impact on a Vertical Wall

• 发表时间: 2015-04
• 作者: F. Gao;J. Zang;C. Blenkinsopp