MODELLING TSUNAMIS FROM RECONSTRUCTED LANDSLIDE SCENARIOS USING SPH

使用 SPH 对重建滑坡场景中的海啸进行建模

• 批准号: NE/F012500/1
• 金额: $ 9.22万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF012500%2F1
• 关键词: MODELLING; TSUNAMIS; RECONSTRUCTED; LANDSLIDE; SCENARIOS

OVERALL OBJECTIVES This project is to use Smoothed Particle Hydrodynamics (SPH) to examine the generation of tsunami waves by realistic landslides. SPH is an innovative meshless computational technique ideal for potentially violent free-surface hydrodynamics. We will address the important issues of identifying the best techniques for modelling landslides in the context of predicting the resultant hydrodynamics, validate with experimental lab data (Fritz et al. 2004), apply to cases using real field data (e.g. Masson et al. 2002), simulate and identify effects of different landslide mechanisms on tsunami generation. OVERVIEW The impacts of tsunamis can be catastrophic as demonstrated by the Indian Ocean tsunami of 2004. While many are the result of earthquake excitation of the sea-bed, equally dangerous are tsunamis generated from landslides such as the Stromboli tsunami. The importance of understanding and reducing the destructive effects of tsunamis cannot be overstated. The identification of submarine landslide prone areas and characterisation of tsunami sources are quite advanced, but the ability to model accurately combined failure mechanisms and tsunami generation from landslides still needs development. Until now, modelling of landslide-generated tsunamis has represented a formidable challenge requiring fully 3-D multiphase numerical models. SPH offers a unique approach to simulate such difficult problems. Based on a representation of the fluid body by large volumes of water subject to Newton's 2nd Law, SPH does not require fixed computational grids so the domain can be multiply connected making modelling of violent free-surface flows straightforward. Application of SPH to landslide-generated tsunamis is a natural extension of the method. Monaghan et al. (2003) modelled the 2-D wave runup from blocks sliding down slopes on runners. Rogers & Dalrymple (2007) have modelled tsunami-initiation using deforming bed slopes and sliding blocks with prescribed motion. The application to deformable sliding masses has also been attempted by SPH with only partial success and needs development. Thus, many areas of research still exist where our knowledge and predictive capability requires substantial improvement. Namely (i) to try to understand how different landslide mechanisms affect generation (single instantaneous failure vs more gradual retrogressive failure), and (ii) the optimum method for simulating landslides and interaction with surrounding water. WORK PROGRAMME Months 1-6 Literature Survey & Preliminary Work Research Student (RS) carries out literature survey of numerical modelling of landslides and SPH. RS familiarises themselves with existing SPH code, SPHysics (our recently released open-source code). Months 7-16 Modelling combined landslide & hydrodynamics RS investigates optimum method for simulating landslides in the context of predicting the resultant hydrodynamics: modelling landslide as heavy water, individual rocks or deforming boundaries. Investigate possibility of coupling SPH with the Discrete Element Model (for the landslide). 1st-year report prepared. Months 17-32 Model Verification & Application Apply to experimental laboratory data on landslides to validate model paying close attention to runup, generated wave heights, resolution for convergence studies and landslide dynamics. Apply validated model to a series of increasingly complex landslide cases based on real data provided by National Oceanography Centre investigating effects of different landslide mechanisms on tsunami generation. Months 24-28 (concurrent) Model Coupling & Parallelisation of new Code If necessary, RS will include coupling of SPH to a longwave propagation model (development already underway at Johns Hopkins University, an international collaborator on SPHysics). RS will add new code developments to previously developed SPHysics parallel code. Months 33-36 Dissemination RS prepares final thesis & papers

总体目标 该项目旨在使用平滑粒子流体动力学 (SPH) 来检查真实山体滑坡所产生的海啸波。 SPH 是一种创新的无网格计算技术，非常适合潜在的剧烈自由表面流体动力学。我们将解决在预测由此产生的流体动力学的背景下确定滑坡建模最佳技术的重要问题，用实验实验室数据进行验证（Fritz 等人，2004 年），应用于使用真实现场数据的案例（例如 Masson 等人，2002 年） ），模拟并识别不同滑坡机制对海啸产生的影响。概述 海啸的影响可能是灾难性的，2004 年印度洋海啸就证明了这一点。虽然许多海啸是海床地震激发的结果，但同样危险的是由山体滑坡引发的海啸，例如斯特龙博利海啸。了解和减少海啸破坏性影响的重要性怎么强调也不为过。海底滑坡易发区的识别和海啸源的表征相当先进，但精确模拟滑坡组合破坏机制和海啸产生的能力仍需发展。到目前为止，山体滑坡引发的海啸建模一直是一项艰巨的挑战，需要完全 3D 多相数值模型。 SPH 提供了一种独特的方法来模拟此类难题。基于遵循牛顿第二定律的大量水对流体体的表示，SPH 不需要固定的计算网格，因此域可以多重连接，从而使暴力自由表面流的建模变得简单。 SPH 应用于滑坡引发的海啸是该方法的自然延伸。莫纳汉等人。 (2003) 对跑步者从斜坡上滑下的块体的二维波浪助跑进行了建模。 Rogers 和 Dalrymple (2007) 使用变形的河床斜坡和具有指定运动的滑块模拟了海啸的发生。 SPH 也尝试将其应用于可变形滑动质量，但仅取得部分成功，需要进一步开发。因此，许多研究领域仍然存在，我们的知识和预测能力需要大幅改进。即（i）尝试了解不同的滑坡机制如何影响发电（单一瞬时破坏与更渐进的倒退破坏），以及（ii）模拟滑坡和与周围水相互作用的最佳方法。工作计划 第 1-6 个月 文献调查和初步工作 研究学生 (RS) 进行滑坡和 SPH 数值模拟的文献调查。 RS 熟悉现有的 SPH 代码 SPHysics（我们最近发布的开源代码）。第 7-16 个月 滑坡和水动力组合建模 RS 研究了在预测所产生的水动力的背景下模拟滑坡的最佳方法：将滑坡建模为重水、单个岩石或变形边界。研究将 SPH 与离散元模型（针对滑坡）耦合的可能性。已准备好第一年报告。第 17-32 个月 模型验证和应用 应用滑坡实验实验室数据来验证模型，密切关注上升、产生的波高、收敛研究的分辨率和滑坡动力学。根据国家海洋学中心提供的真实数据，将经过验证的模型应用于一系列日益复杂的滑坡案例，调查不同滑坡机制对海啸产生的影响。第 24-28 个月（并发） 新代码的模型耦合和并行化 如果有必要，RS 将包括 SPH 与长波传播模型的耦合（约翰霍普金斯大学已经在进行开发，该大学是 SPHysics 的国际合作者）。 RS 将在之前开发的 SPHysics 并行代码中添加新的代码开发。第 33-36 个月 传播 RS 准备期末论文和论文