Mini Special Issue on Tsunami Numerical Modeling Benchmarks – Challenges of Tsunami Modeling Hackathon –

Numerical simulation and modeling became an essential technology in tsunami research and disaster management. Various numerical models were proposed and utilized for the development of tsunami risk assessment, inundation maps, and evacuation plans. The model verification and validation standards would be crucial to ensure sufficient reliability of tsunami risk assessment, inundation maps, as well as a consistency among various efforts. Common approach to ensure sufficient accuracy and reliability of numerical modeling is developing benchmark problems of hydraulic experiments and to use them for numerical model’s verification and validation. To satisfy this requirement, “Tsunami Modeling Hackathon” was held in September 2020 to organize new benchmark problems in numerical modeling of tsunamis and to improve their reliability and accuracy. Hackathon is an intensive-gathering event of computer programmers and others involved in software development to create outcomes by the end of the event. This event was organized by Prof. Tomoyuki Takahashi of Kansai University and his colleagues, who led the tsunami research subcommittee in Japan Society of Civil Engineers (JSCE). Tsunami modeling hackathon, in which about 23 teams and 162 researchers joined, included experiment and modeling teams in seven benchmark problems: urban tsunami inundation, landslide tsunami, tsunami loading on seawalls and coastal structures, sediment transport, drift of floating objects. The modeling groups performed the blind tests to cross-validate and interpret the results of their simulations in seven benchmark problems given by the experiment groups and discussed the improvement. This special issue reports the outcomes of the tsunami modeling hackathon, and includes six papers (five in this issue, one in the regular issue). We hope this issue will provide useful insights for tsunami modelers and contribute to establishing a standardized way to ensure that various tsunami numerical models would be validated through the benchmark problems.

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Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽

10.3390/w13040458 ◽

2021 ◽

Vol 13 (4) ◽

pp. 458

Author(s):

Drew C. Baird ◽

Benjamin Abban ◽

S. Michael Scurlock ◽

Steven B. Abt ◽

Christopher I. Thornton

Keyword(s):

Numerical Modeling ◽

Physical Model ◽

Numerical Models ◽

Hydraulic Performance ◽

Physical Models ◽

Protection Measures ◽

Design Engineers ◽

Model Study ◽

Study Results ◽

Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

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Special Issue “Applications of Finite Element Modeling for Mechanical and Mechatronic Systems”

Applied Sciences ◽

10.3390/app11115170 ◽

2021 ◽

Vol 11 (11) ◽

pp. 5170

Author(s):

Marek Krawczuk ◽

Magdalena Palacz

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Numerical Modeling ◽

Engineering Practice ◽

The Finite Element Method ◽

Special Issue ◽

Mechatronic Systems ◽

Modeling And Analysis ◽

Modern Engineering ◽

Concise Description

Modern engineering practice requires advanced numerical modeling because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim of this Special Issue has been to familiarize the reader with the latest applications of the FEM for the modeling and analysis of diverse mechanical problems. Authors are encouraged to provide a concise description of the specific application or a potential application of the Special Issue.

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Special Issue: Advanced numerical modeling and algorithms for multiphase flow and transport

Journal of Computational Physics ◽

10.1016/j.jcp.2019.109222 ◽

2020 ◽

Vol 408 ◽

pp. 109222

Author(s):

Yalchin Efendiev ◽

Abbas Firoozabadi ◽

Shuyu Sun ◽

Mary F. Wheeler ◽

Bo Yu

Keyword(s):

Numerical Modeling ◽

Multiphase Flow ◽

Special Issue ◽

Flow And Transport

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Numerical modeling of the hydraulic impact of riparian vegetation

E3S Web of Conferences ◽

10.1051/e3sconf/20184400194 ◽

2018 ◽

Vol 44 ◽

pp. 00194

Author(s):

Krzysztof Wolski ◽

Tomasz Tymiński ◽

Grzegorz Chrobak

Keyword(s):

Numerical Modeling ◽

Riparian Vegetation ◽

Water Surface ◽

Numerical Models ◽

Three Dimensional ◽

Careful Examination ◽

Impact Structure ◽

Hydraulic Impact ◽

Vegetation Zones ◽

Maximal Shear Stress

This paper presents results of numerical modelling of riverbed segment with riparian vegetation performed with use of CCHE2 software. Vegetation zones are places where dynamic of water flow increases. Therefore, there is a need of careful examination of hydraulic impact structure of such zones. Accurate research is necessary and should be performed with use of physical or numerical models, two or three dimensional. Paper presents distribution of velocity and area of water surface for two variants of vegetation deposition acquired in CCHE2D software and modelled for riverbed with distinctive riparian vegetation. Results point to significant (30–40%) increase of maximal velocities in riverbed with riparian vegetation, while directly near the vegetation there were zones with very low velocities. Local damming occurs before vegetal zone. Maximal shear stress in zones with increased velocity is significantly augmented compared to conditions with no vegetation, which can cause more intensive erosion in those zones

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Foreword to the special issue on hydraulic and numerical modeling studies

ISH Journal of Hydraulic Engineering ◽

10.1080/09715010.2019.1539386 ◽

2018 ◽

Vol 25 (1) ◽

pp. 1-2 ◽

Cited By ~ 1

Keyword(s):

Numerical Modeling ◽

Special Issue ◽

Modeling Studies

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Numerical Modeling of a Punch Penetration Test Using the Discrete Element Method

Slovak Journal of Civil Engineering ◽

10.2478/sjce-2020-0008 ◽

2020 ◽

Vol 28 (2) ◽

pp. 1-7

Author(s):

Rouhollah Basirat ◽

Jafar Khademi Hamidi

Keyword(s):

Numerical Modeling ◽

Discrete Element Method ◽

Numerical Models ◽

Confining Pressure ◽

Discrete Element ◽

Numerical Results ◽

Strength Parameter ◽

Penetration Test ◽

Strength Parameters ◽

Element Method

AbstractUnderstanding the brittleness of rock has a crucial importance in rock engineering applications such as the mechanical excavation of rock. In this study, numerical modeling of a punch penetration test is performed using the Discrete Element Method (DEM). The Peak Strength Index (PSI) as a function of the brittleness index was calculated using the axial load and a penetration graph obtained from numerical models. In the first step, the numerical model was verified by experimental results. The results obtained from the numerical modeling showed a good agreement with those obtained from the experimental tests. The propagation path was also simulated using Voronoi meshing. The fracture was created under the indenter in the first step, and then radial fractures were propagated. The effects of confining pressure and strength parameters on the PSI were subsequently investigated. The numerical results showed that the PSI increases with enhancing the confining pressure and the strength parameter of the rock, including cohesion and the friction angle. A new relationship between the strength parameters and PSI was also introduced based on two variable regressions of the numerical results.

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Numerical modeling of hiding properties of underwater acoUStic communication signals with linear sweep of the carrier

Podvodnye issledovaniia i robototehnika ◽

10.37102/24094609.2020.32.2.001 ◽

2020 ◽

Author(s):

К.Г. Кебкал

Keyword(s):

Numerical Modeling ◽

Continuous Spectrum ◽

Gaussian Noise ◽

Data Exchange ◽

Numerical Models ◽

Underwater Acoustic Communication ◽

Underwater Acoustic ◽

Communication Signals ◽

Communication Signal ◽

Spectrum Spread

На результатах численного моделирования продемонстрировано, что распределения вероятностей огибающей и фазы смеси гауссова шума и (слабого) гидроакустического сигнала связи, характеризуемого линейной разверткой несущей, могут иметь исчезающе малые отличия от аналогичных распределений, характерных для просто гауссова шума. Использование непрерывного расширения спектра сигнала связи может представлять интерес для задач скрытого обмена данными, в которых обнаружение сеанса связи устройствами перехвата должно быть затруднительным или невозможным. С применением численных моделей проанализированы возможности использования сигналов с непрерывным расширением спектра для скрытой цифровой гидроакустической связи посредством штатных приемоизлучающих гидроакустических систем, находящихся на вооружении действующих кораблей. Based on the results of the numerical modeling, the vanishingly small differences between the probability distributions of the envelope and phase of the sum of Gaussian noise and (weak) underwater acoustic signal with linear carrier sweep, and the same distributions for the Gaussian noise all alone are demonstrated. Utilization of the continuous spectrum spread of the communication signal may be applied to the task of covert data exchange, where detection of the communication session by the intercepting equipment must be complicated or impossible. Using numerical models, we analyzed the capabilities of implementation of the signals with continuous spectrum spread for covert digital underwater acoustic communications through the standard underwater acoustic transducers, which are in service on the operational ready vessels.

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