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

本计画将利用平滑粒子流体动力学（SPH）来研究真实山崩所产生的海啸波。SPH是一种创新的无网格计算技术，非常适合于潜在的剧烈自由表面流体动力学。我们将解决的重要问题，确定最好的技术来模拟滑坡的背景下，预测所产生的流体动力学，验证实验室的实验数据（弗里茨等，2004年），适用于使用真实的现场数据的情况下（例如，马森等，2002年），模拟和识别不同的滑坡机制对海啸生成的影响。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。虽然许多海啸是地震激发海床的结果，但同样危险的是由山体滑坡产生的海啸，如斯特龙博利海啸。理解和减少海啸的破坏性影响的重要性怎么强调都不过分。海底滑坡易发区的识别和海啸源的表征是相当先进的，但准确地结合故障机制和海啸的滑坡生成模型的能力仍然需要发展。到目前为止，滑坡产生的海啸的建模是一个艰巨的挑战，需要全三维多相数值模型。SPH提供了一种独特的方法来模拟这些困难的问题。基于牛顿第二定律的大量水的流体表示，SPH不需要固定的计算网格，因此该域可以多次连接，从而直接建模剧烈的自由表面流动。应用SPH滑坡产生的海啸是一个自然的扩展方法。Monaghan等人（2003年）模拟了从滑道斜坡上滑下的块体的二维波浪爬高。Rogers &达林普尔（2007）利用变形的河床斜坡和具有预定运动的滑动块来模拟海啸的引发。SPH也曾尝试将其应用于可变形滑动体，但只取得了部分成功，需要进一步发展。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提高。即（i）试图了解不同的滑坡机制如何影响生成（单一瞬时破坏与更渐进的后退破坏），以及（ii）模拟滑坡及其与周围水相互作用的最佳方法。工作计划1-6月文献调查和前期工作研究生（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）。月7-16滑坡与水动力学联合建模RS研究在预测最终水动力学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。调查SPH与离散元模型（用于滑坡）耦合的可能性。编写第一年报告。Months 17-32模型验证与应用应用于滑坡的实验室数据，验证模型，密切关注爬高、生成的波高、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的数据，将经过验证的模型应用于一系列日益复杂的滑坡案例，以调查不同滑坡机制对海啸生成的影响。第24-28个月（同期）模型耦合和新代码的并行化如果需要，RS将包括SPH到长波传播模型的耦合（SPHysics的国际合作者约翰霍普金斯大学已经在进行开发）。RS将在以前开发的SPHysics并行代码中添加新的代码开发。33-36个月传播RS准备最后的论文和论文