scholarly journals Hydrodynamic Modelling of Wave Overtopping over a Block-Covered Flood Defence

2022 ◽  
Vol 10 (1) ◽  
pp. 89
Author(s):  
Luuk Barendse ◽  
Vera M. van Bergeijk ◽  
Weiqiu Chen ◽  
Jord J. Warmink ◽  
Aroen Mughal ◽  
...  
Keyword(s):  
Numerical Model ◽  
Porous Layer ◽  
Hydrodynamic Condition ◽  
Hydrodynamic Conditions ◽  
Physical Test ◽  
Wave Overtopping ◽  
Physical Tests ◽  
Run Up ◽  
Resistance Coefficients ◽  
Flow Velocities

Wave overtopping can cause erosion on the landward slope due to high flow velocities and turbulence that cause high stresses on the cover. Innovative block revetments such as Grassblocks protect the subsoil of the dike against erosion. The blocks are permeable, which reduces the flow velocity and the pressures along the landward slope. The performance of these blocks is assessed in physical tests, which provides insights into the stability of the blocks. However, such experiments are expensive and accurate measurements are difficult due to highly turbulent conditions. Therefore, the goal of this study is to determine the hydrodynamic conditions at the dike cover caused by the wave run-up on the seaward slope and by the overtopping flow over the crest and landward slope. The geometry and wave conditions from the physical test at the Deltares Delta flume are implemented in an OpenFOAM® numerical model. Using the porousWaveFoam solver, a porous layer on the crest and landward slope is implemented, where the flow resistance of this porous layer largely depends on the resistance coefficients α [-] and β [-]. The numerical model is calibrated based on resistance coefficients as introduced earlier in the literature, which showed that the resistance coefficients of α=500 and β=2.0 performed best for the peak flow velocities and the peak pressures. The numerical model is evaluated by using these resistance coefficients in other time series of the physical tests. The evaluated model is then used to determine the hydrodynamic conditions on the landward slope, which showed that the pressure was the most influential hydrodynamic condition at the time of failure. Finally, the model showed that a porosity of n=0.6 and the porous layer thickness η=36mm reduced the peak pressure the most.

scholarly journals KONDISI HIDRODINAMIKA PERAIRAN SUNGAI LIAT BANGKA BERDASARKAN MODEL MIKE 21-HD-AD SEHUBUNGAN DENGAN MORFOLOGI AKIBAT PENAMBANGAN DI LAUT

2016 ◽  
Vol 10 (1) ◽  
pp. 39
Author(s):  
Franto Novico ◽  
Citrawan Sinaga
Keyword(s):  
Numerical Model ◽  
River Mouth ◽  
Mining Operation ◽  
Hydrodynamic Condition ◽  
Hydrodynamic Conditions ◽  
Sea Floor ◽  
Mine Dumps ◽  
The North ◽  
Maximum Current ◽  
Mike 21

Penambangan timah di perairan sekitar Sungai Liat- Bangka oleh kapal keruk dan hisap telah menyebabkan terjadinya perubahan kondisi dasar laut yang sangat besar dengan ditemukannya batimetri yang sangat tidak beraturan di sekitar wilayah foreshore, terutama pada bagian barat muarasungai. Pendekatan model numerik dengan menggunakan software Mike 21 HD-AD menjadi metode pilihan untuk mendapatkan gambaran kondisi hidrodinamika sekitar muara dan garis pantai sekitar Sungai Liat. Berdasarkan hasil simulasi didapatkan bahwa dengan perkiraan pelaksanaan kegiatan penambangan 24 jam sehari selama 15 hari model operasi maka kondisi sebaran buangan akan terbawa hingga jarak terjauh 15 km ke arah selatan, sementara sebaran bergerak ke arah utara sejauh 5 km dari lokasi sumber buangan. Waktu yang dibutuhkan untuk sebaran mencapai garis pantaiadalah 27 jam setelah penambangan dioperasikan. Sementara nilai kecepatan arus maksimum pada saat bulan penuh sebesar 1.5 m/det dengan arah arus dominan ke utara sementara pada saat bulan mati kecepatan maksimum sebesar 1.2 m/det dengan arah arus dominan ke tenggara. Kata kunci : Kondisi Hidrodinamika Sungai Liat, Model Numerik, Buangan Tambang The mining activities using dredging vessel and suction vessel that have done near river mouth of Sungai Liat and along coast line yielded a big deformation of sea floor bathymetry at foreshore especially west side a river mouth. Mike 21 HD-AD software as numerical model was selected as method to describe hydrodynamic conditions around river mouth and along coastline near the Sungai Liat River. Based on simulations where the mining operation is predicted 24 hours a day within 15 days operation model therefore a range of outsource dispersion of 15 km to south while 5 km flows to the north from the mine dumps position. A dispersion of mine dumps would be achieve a coastline in 27 hours since the mining begun. In addition, maximum current in spring time shows 1.5 m/sec to the north direction whereas in neap time the current shows 1.2 m/sec to the southeast direction. Keywords: Hydrodynamic Condition, Sungai Liat, Numerical Model, Mine dumps

scholarly journals APPLICATION OF SMOOTHED PARTICLE HYDRODYNAMICS IN EVALUATING THE PERFORMANCE OF COASTAL RETROFIT STRUCTURES

2018 ◽  
pp. 109 ◽  
Author(s):  
Soroush Abolfathi ◽  
Dong Shudi ◽  
Sina Borzooei ◽  
Abbas Yeganeh-Bakhtiari ◽  
Jonathan Pearson
Keyword(s):  
Numerical Model ◽  
Smoothed Particle Hydrodynamics ◽  
Vertical Wall ◽  
Laboratory Data ◽  
Wave Structure ◽  
Base Case ◽  
Submerged Breakwater ◽  
Wave Overtopping ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

This study develops an accurate numerical tool for investigating optimal retrofit configurations in order to minimize wave overtopping from a vertical seawall due to extreme climatic events and under changing climate. A weakly compressible smoothed particle hydrodynamics (WCSPH) model is developed to simulate the wave-structure interactions for coastal retrofit structures in front of a vertical seawall. A range of possible physical configurations of coastal retrofits including re-curve wall and submerged breakwater are modelled with the numerical model to understand their performance under different wave and structural conditions. The numerical model is successfully validated against laboratory data collected in 2D wave flume at Warwick Water Laboratory. The findings of numerical modelling are in good agreement with the laboratory data. The results indicate that recurve wall is more effective in mitigating wave overtopping and provides more resilience to coastal flooding in comparison to base-case (plain vertical wall) and submerged breakwater retrofit.

scholarly journals PHYSICAL MODEL TESTS ON WAVE OVERTOPPING AND FLOW PROCESSES ON DIKE CRESTS INFLUENCED BY WAVE-CURRENT INTERACTION

2012 ◽  
Vol 1 (33) ◽  
pp. 34 ◽  
Author(s):  
Stefanie Lorke ◽  
Babette Scheres ◽  
Holger Schüttrumpf ◽  
Antje Bornschein ◽  
Reinhard Pohl
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Longshore Current ◽  
Wind Fields ◽  
Incoming Wave ◽  
Wave Overtopping ◽  
Improve Design ◽  
Physical Model Tests ◽  
Flow Processes ◽  
Run Up

Flow processes like flow depths and flow velocities give important information about erosion and infiltration processes, which can lead to an unstable dike structure and consequently to dike failure. Up to now several physical model tests on wave run-up and wave overtopping are available to adjust and improve design formula for different dike structures. This kind of physical model tests have been performed in the here presented project FlowDike. Its main purpose is to consider two new aspects that could influence the assessment of wave run-up and wave overtopping as well as the flow processes on dikes which have not been investigated yet: longshore current and wind. Especially in estuaries and along coasts, the effect of tidal and storm induced currents combined with local wind fields can influence the incoming wave parameters at the dike toe as well as the wave run-up height, the wave overtopping rate and the flow processes on dikes. This paper will focus on these flow processes on dike slopes and dike crests on an 1:6 sloped dike influenced by oblique wave attack and longshore current.

scholarly journals THE WAVE RUN-UP SIMULATOR, THEORY AND FIRST PILOT TEST

2012 ◽  
Vol 1 (33) ◽  
pp. 65 ◽  
Author(s):  
Jentsje Van der Meer ◽  
Yvo Provoost ◽  
Gosse Jan Steendam
Keyword(s):  
Prediction Method ◽  
Pilot Test ◽  
Wave Overtopping ◽  
Run Up

The idea of the Wave Run-up Simulator is based on the experiences with the Wave Overtopping Simulator. It is possible to simulate wave tongues overtopping a dike crest in reality. It must also be possible to simulate waves in the run-up and run-down zone of the seaward slope. This is the zone after waves have broken and when they rush-up the slope. The present paper describes this new idea of the Wave Run-up Simulator, why it is useful to develop the machine, to perform research with it and to develop a prediction method for slope strength. In fact, a prediction method can already be developed from the Cumulative Overload Method, which was developed on the basis of results with the Wave Overtopping Simulator, see Van der Meer et al. (2010). It also means that tests on the seaward slope will be done for validation purposes only. The paper describes in detail what is known about the movement of waves in this run-up zone and what actually the Wave Run-up Simulator has to simulate. Not a lot of research has been performed to describe the wave run-up process in detail, physically nor statistically. Finally, the pilot test has been described including hydraulic measurements on the slope.

scholarly journals Non-breaking and breaking solitary wave run-up

2002 ◽  
Vol 456 ◽  
pp. 295-318 ◽  
Author(s):  
YING LI ◽  
FREDRIC RAICHLEN
Keyword(s):  
Numerical Model ◽  
Solitary Wave ◽  
Wave Breaking ◽  
Ad Hoc ◽  
Mapping Technique ◽  
Breaking Wave ◽  
Good Prediction ◽  
Computational Domain ◽  
Domain Mapping ◽  
Run Up

The run-up of non-breaking and breaking solitary waves on a uniform plane beach connected to a constant-depth wave tank was investigated experimentally and numerically. If only the general characteristics of the run-up process and the maximum run-up are of interest, for the case of a breaking wave the post-breaking condition can be simplified and represented as a propagating bore. A numerical model using this bore structure to treat the process of wave breaking and subsequent shoreward propagation was developed. The nonlinear shallow water equations (NLSW) were solved using the weighted essentially non-oscillatory (WENO) shock capturing scheme employed in gas dynamics. Wave breaking and post-breaking propagation are handled automatically by this scheme and ad hoc terms are not required. A computational domain mapping technique was used to model the shoreline movement. This numerical scheme was found to provide a relatively simple and reasonably good prediction of various aspects of the run-up process. The energy dissipation associated with wave breaking of solitary wave run-up (excluding the effects of bottom friction) was also estimated using the results from the numerical model.

Physical function tests predict incident falls: A prospective study of 2969 men in the Swedish Osteoporotic Fractures in Men study

2018 ◽  
Vol 48 (4) ◽  
pp. 436-441 ◽  
Author(s):  
Marcus E. Cöster ◽  
Magnus Karlsson ◽  
Claes Ohlsson ◽  
Dan Mellström ◽  
Mattias Lorentzon ◽  
...  
Keyword(s):  
Grip Strength ◽  
Osteoporotic Fractures ◽  
The Elderly ◽  
Population Based ◽  
Hand Grip Strength ◽  
Test Time ◽  
Physical Test ◽  
Walking Test ◽  
Hand Grip ◽  
Physical Tests

Aims: Falls are common in the elderly population, and fall-related injuries are a major health issue. We investigated the ability of simple physical tests to predict incident falls. Methods: The Swedish Osteoporotic Fractures in Men (MrOS) study includes 3014 population-based men aged 69–81 years at the start of the study. These men performed five different physical tests at baseline: right-hand grip strength, left-hand grip strength, timed stand test, 6 m walking test (time and steps) and narrow walking test. During the first study year, we asked participants to fill out questionnaires regarding falls 4, 8 and 12 months after baseline. A total of 2969 men completed at least one questionnaire and were included in this study. We used generalised estimating equations and logarithmic regression models to estimate odds ratios for fallers and recurrent fallers (more than one fall during the one-year examination period) in each quartile of men for each physical test. Results: The proportions of fallers and recurrent fallers were higher in the lowest quartile of the physical tests than in the other three quartiles combined for all physical tests. A reduction of one standard deviation in respective physical test resulted in a 13–21% higher risk of becoming a faller and a 13–31% higher risk of becoming a recurrent faller. Conclusions: Low results on simple physical tests is a risk factor for incident falls in elderly Swedish men and may facilitate identification of high-risk individuals suitable for fall-intervention programs.

scholarly journals Supervised and home-based physical exercise in patients newly diagnosed with multiple myeloma—a randomized controlled feasibility study

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Rikke Faebo Larsen ◽  
Mary Jarden ◽  
Lisbeth Rosenbek Minet ◽  
Ulf Christian Frølund ◽  
Niels Abildgaard
Keyword(s):  
Multiple Myeloma ◽  
Bone Disease ◽  
Exercise Intervention ◽  
Newly Diagnosed ◽  
Test Procedures ◽  
Physical Test ◽  
Randomized Controlled ◽  
Supervised Exercise ◽  
Home Based ◽  
Physical Tests

Abstract Background The study evaluated the feasibility and safety of the exercise intervention and physical test procedures of our ongoing randomized controlled trial, examining the effect of physical exercise in newly diagnosed patients with multiple myeloma. Methods Patients are randomized 1:1 to a control group (usual care) or an intervention group (usual care and exercise) by block randomization with stratification of planned treatment, WHO performance status, and study site. The exercise intervention consists of eight supervised exercise sessions combined with home-based exercise over a 10-week period. Bone disease is systematically evaluated to determine limitations regarding physical testing and/or exercise. Feasibility outcome measures were study eligibility, acceptance, and attrition, and furthermore attendance, adherence, tolerability, and safety to the exercise intervention. Additionally, test completion, pain, and adverse events during the physical test procedures were evaluated. Outcome assessors were blinded to allocation. Results Of 49 patients screened, 30 were included. The median age was 69 years, range 38–90, 77% were males, and 67% had bone disease. Study eligibility was 82%, acceptance 75%, and attrition 20%. Attendance at supervised exercise sessions was 92%, and adherence to supervised exercise sessions and home-based exercise sessions was 99% and 89%, respectively. No serious adverse events attributed to exercise or physical tests were reported. All patients completed the physical tests, except for two patients, where physical test procedures were modified due to bone disease. Discussion The exercise intervention and physical test procedures were feasible and safe in patients with multiple myeloma, even in older patients with multiple myeloma and in patients with myeloma bone disease. Trial registration ClinicalTrials.gov. ID NCT02439112. Registered on May 7, 2015.

Review of current research trends in bird strike and hail impact simulations on wing leading edge

2018 ◽  
Vol 90 (4) ◽  
pp. 602-612 ◽  
Author(s):  
Zdobyslaw Jan Goraj ◽  
Kamila Kustron
Keyword(s):  
Computer Simulations ◽  
Leading Edge ◽  
Simulation Models ◽  
Bird Strike ◽  
Physical Test ◽  
Content Type ◽  
Physical Tests ◽  
Statistical Approaches ◽  
The Impact ◽  
Hail Impact

Purpose Bird strike and hail impact resistances are considered in relation to the fulfilment of airworthiness/crashworthiness regulations as specified by appropriate aviation authorities. Before aircraft are allowed to go into service, these regulations must be fulfilled. This includes the adaption of the wing leading edge (LE) structure to smart diagnostics and an easy repair. This paper aims to focus on the wing LE, although all forward-facing aircraft components are exposed to the impact of foreign object during the flight. The best practices based on credible simulations which may be appropriate means of establishing compliance with European Aviation safety Agency and Federal Aviation Administration regulations regarding bird strikes, together with the problem of collisions with hailstones, are overviewed in aspect of accuracy and computing cost. Design/methodology/approach The best means of evaluating worldwide certification standards so as to be more efficient for all stakeholders by reducing risk and costs (time and money consuming) of certification process are recommended. The very expensive physical tests may be replaced by adequate and credible computer simulations. The adequate credible simulation must be verified and validated. The statistical approaches for modelling the uncertainty are presented in aspect of computing cost. Findings The simulation models have simplifications and assumptions that generate an uncertainty. The uncertainty must be identified in benchmarking tests. Instead of using “in house” physical tests, there are scientific papers available in open literature thanks to the new trend in worldwide publication of the research results. These large databases can be efficiently transform into useful benchmark thanks to data mining and knowledge discovery methods and big data analyses. The physical test data are obtained from tests on the ground-based demonstrator by using high-speed cameras and a structural health monitoring system, and therefore, they should be applied at an early stage of the design process. Originality/value The sources of uncertainty in simulation models are expressed, and the way to their assessment is presented based on statistical approaches. A brief review of the current research shows that it widely uses efficient numerical analysis and computer simulations and is based on finite element methods, mesh structure as well as mesh free particle models. These methods and models are useful to analyse airworthiness requirements for damage tolerance regarding bird-strike and hail impact and haves been subjected to critical review in this paper. Many original papers were considered in this analysis, and some of them have been critically reviewed and commented upon.

Evaluation of Cumulative Damage From Drop to Puncture Conditions

2012 ◽  
Author(s):  
Woo-Seok Choi ◽  
Sanghoon Lee ◽  
Kyoung-Sik Bang ◽  
Ju-Chan Lee ◽  
Ki-Seog Seo
Keyword(s):  
Numerical Simulations ◽  
Initial Conditions ◽  
Water Immersion ◽  
Cumulative Damage ◽  
Single Event ◽  
Physical Test ◽  
Sequential Event ◽  
Physical Tests ◽  
Hypothetical Accident ◽  
Accident Conditions

During safety assessments of transport packages, cumulative damages are naturally accumulated for assessments performed using physical tests specimens. However, the cumulative damages are not as easily accounted when assessments are by numerical simulations. While analysts are comfortable with simulating packages for single events, it is not yet common practice to incorporate the effect handed over from a former event to the next, in a series of sequential load events. Thus, many numerical simulations in SAR (Safety Analysis Report) represent just a single event in the series of sequential event comprising the required accident condition. These single event numerical simulations are then based on initial conditions different from the analogous physical test specimen, which could contribute to a growing disparity in results between assessments by physically testing compared to numerical simulation. The reason why analyses do not consider the cumulative damage is difficulties in delivering the final result of the previous analysis to the current analysis. The hypothetical accident conditions described in the IAEA regulations include drop, puncture, fire, and water immersion conditions, which should be sequentially simulated. There can be cumulative damage between two accident conditions, such as drop and puncture, puncture and fire, and so forth. In this study, as the first step to consider cumulative damage, an analysis technology to perform a puncture analysis incorporating the final response field from a prior drop analysis is proposed. The necessity and validity of the proposed analysis technology are evaluated by a comparison with the results obtained by performing each analysis independently.

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