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.

FROTH项目是五所大学之间的密切合作，这些大学在研究波浪与固定和浮动结构的相互作用方面具有丰富的经验，它们共同努力，将联合收割机结合起来，并将其专业知识应用于问题的不同方面。其目的是通过一个精心整合的大规模数值模拟和物理实验方案，研究刚性和弹性结构上剧烈水动力冲击载荷的详细物理学。将开发开放源代码数值代码，以模拟在UoP新的国家波浪和海流设施中进行的实验室实验[http://www.plymouth.ac.uk/pages/view.asp? page=34369]。众所周知，气候变化将导致英国和欧洲西北部近海海洋环境中的海平面上升和风暴活动增加（更严重的个别风暴或更多风暴，或两者兼而有之）。这对现有海上结构上的人员安全以及现有和新类型的LNG运输船的安全操作具有关键影响，现有和新类型的LNG运输船的结构由于在恶劣的海洋中运输液体的剧烈晃动而受到大的瞬时载荷。英国沃茨中的一些现有石油和天然气海上结构已经使用了40年，这些老化的结构需要重新评估，以确保它们能够承受由于气候变化而增加的载荷，并确认它们的寿命可以延长到未来25年。升级这些现有结构物和确保新结构物和船舶的生存能力和安全运行的成本将主要取决于水动力冲击载荷预测的可靠性。这些载荷会对海堤、为晃动液体提供密封的储罐（例如液化天然气运输船）造成严重损坏，并对浮式生产储油卸油轮（FPSO）和其他海上浮式结构（例如波浪能转换器）造成损坏。虽然对大量流体的流体动力学了解相对较好，但水面的剧烈运动和破碎仍然是工程设计中需要足够准确模拟的主要挑战。虽然自由表面高度和平均载荷通常通过分析技术相对较好地预测，但在这种极端条件下观察到的瞬时峰值压力不能可靠地预测，并且即使在仔细控制的实验室实验中也常常不可重复。关于流体动力冲击载荷的详细物理学，即使是对于固定结构和可能发生的极高压力脉冲，仍然存在许多深刻的基本未决问题。特别是，在理解以下因素的影响方面存在不确定性：（包括截留的囊袋和夹带的气泡），因为水的声学性质改变，导致实验中测量的波浪冲击压力的可变性;结构的柔性，导致水弹性响应;陡度和入射波的三维度。该建议旨在直接攻击这一根本困难和安全-通过一系列紧密集成的实验室实验和最先进的数值模拟来解决关键问题，最终目标是为固定和浮动的海上、海洋和沿海结构物的设计者提供更好的指导。

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.

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 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

Numerical Simulations of Breaking Waves at Vertical Wall

垂直壁破碎波的数值模拟

• 发表时间: 2014
• 作者: Gao F.