Emneord:
Mekanikk,
Fluidmekanikk
Publikasjoner
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Su, Pin-Tzu; Didenkulova, Irina & Jensen, Atle
(2025).
Transport of tsunami-driven debris over a slope.
Ocean Engineering.
ISSN 0029-8018.
348.
doi:
10.1016/j.oceaneng.2025.124028.
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We study tsunami-induced transport of heavy and floating debris over a slope. The work is performed experimentally in a small wave flume, which is 3 m long and 0.1 m wide with the water depth of 0.05 m. Tsunami is modeled by breaking solitary waves with amplitude (a), normalized by the water depth (hw) equal to a/hw = 0.5. Three succeeding waves propagate towards a sedimentary beach breaking on the slope, and impact debris which are initially placed at different locations along the slope with respect to the wave breaking point. We use spherical debris with two different densities. The heavy ones are lying on the slope, while the light ones are floating at the surface. The sea bed slope is covered with 0.02 m layer of sand. We use sediments of two different sizes to study the interaction of debris with sedimentary environment. The main measured parameter is displacement of the debris along the slope, which is analyzed with respect to the characteristics (densities) of the debris, their initial positions, number of consecutive waves and the size of the sediments
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Su, Pin-Tzu; Didenkulova, Ira & Jensen, Atle
(2024).
Solitary wave-induced boulder transport on a beach.
Ocean Engineering.
ISSN 0029-8018.
313.
doi:
10.1016/j.oceaneng.2024.119318.
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The influence of sediment on a slope on boulder transport is studied experimentally at the Hydrodynamics Laboratory of the University of Oslo. Experiments are conducted in a small 3 m long and 10 cm wide wave tank, filled with 5 cm of water. The transport of boulders is induced by breaking solitary waves with an amplitude normalized by water depth a/ℎ𝑤 = 0.5. Generated solitary waves propagate towards a 1:10 beach. The experiments are conducted in two set-ups: (i) empty Polymethyl methacrylate (PMMA) bottom of the flume, (ii) the slope covered by a thin layer of 65 μm sand. The boulders are represented by concrete blocks of different shape and size. They are placed alternately (one at a time) at different locations on the beach slope with respect to wave breaking point. Transport of boulders and their dynamics is studied with respect to boulder characteristics (size, orientation), their initial position and inclusion of sediment. It is shown that presence of sediment enhances boulder transport. In particular, in this set-up, the presence of sediment increased the boulder transport in 2–5 times. The maximum displacement increase was observed for boulders with the smallest length and height and the largest width initially located at the breaking position. Another interesting result regards the type of boulder motion. The boulders experienced either sliding or turning over. Boulders whose height was at least twice as large as their length exhibited turning-over. This held for boulders placed both on an empty PMMA slope and on a sedimentary slope. However, the largest boulder displacement on an empty PMMA slope occurred due to turning over, while on a sedimentary slope it occurred due to sliding.
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Meier, H.E. Marcus; Reckermann, Marcus; Langner, Joakim; Smith, Ben & Didenkulova, Ira
(2023).
Overview: The Baltic Earth Assessment Reports (BEAR).
Earth System Dynamics (ESD).
ISSN 2190-4979.
14(2),
s. 519–331.
doi:
10.5194/esd-14-519-2023.
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Baltic Earth is an independent research network of scientists from all Baltic Sea countries that promotes regional Earth system research. Within the framework of this network, the Baltic Earth Assessment Reports (BEARs) were produced in the period 2019–2022. These are a collection of 10 review articles summarising current knowledge on the environmental and climatic state of the Earth system in the Baltic Sea region and its changes in the past (palaeoclimate), present (historical period with instrumental observations) and prospective future (until 2100) caused by natural variability, climate change and other human activities. The division of topics among articles follows the grand challenges and selected themes of the Baltic Earth Science Plan, such as the regional water, biogeochemical and carbon cycles; extremes and natural hazards; sea-level dynamics and coastal erosion; marine ecosystems; coupled Earth system models; scenario simulations for the regional atmosphere and the Baltic Sea; and climate change and impacts of human use. Each review article contains an introduction, the current state of knowledge, knowledge gaps, conclusions and key messages; the latter are the bases on which recommendations for future research are made. Based on the BEARs, Baltic Earth has published an information leaflet on climate change in the Baltic Sea as part of its outreach work, which has been published in two languages so far, and organised conferences and workshops for stakeholders, in collaboration with the Baltic Marine Environment Protection Commission (Helsinki Commission, HELCOM).
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Didenkulova, Ekaterina; Didenkulova, Ira & Medvedev, Igor
(2023).
Freak wave events in 2005-2021: Statistics and analysis of favourable wave and wind conditions.
Natural Hazards and Earth System Sciences.
ISSN 1561-8633.
23(4),
s. 1653–1663.
doi:
10.5194/nhess-23-1653-2023.
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Freak or rogue waves are unexpectedly and abnormally large waves in seas and oceans, which can cause loss of human lives and damage to ships, oil platforms, and coastal structures. Evidence of such waves is widely spread around the globe. The present paper is devoted to analysis of the unified collection of freak wave events from different chronicles and catalogues from 2005 to 2021. The considered rogue waves are not measured in situ data, but their descriptions, which have been found in mass media sources and scientific articles, are the data used. All of them resulted in damage to ships or coastal/offshore structures and/or human losses. The collection accounts for 429 events. First, the analysis based on their characteristics taken from the descriptions of the events (including locations, water depth, damages) is carried out. Second, the analysis of wave parameters taken from the climate reanalysis ERA5 is performed. Thus, the most probable background wave parameters at the time of the freak event (including wind speed, gusts, significant wave height, maximum wave height, peak wave period, skewness, excess kurtosis, Benjamin–Feir instability (BFI), and wave spectral directional width) for each freak wave event are determined.
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Didenkulova, Irina; Zaitsev, Andrey & Pelinovsky, Efim
(2022).
Tsunami Distribution Functions along the Coast: Extended.
Journal of Marine Science and Engineering (JMSE).
10(8),
s. 1–8.
doi:
10.3390/jmse10081137.
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The distribution of tsunami runup heights along the coast is studied both theoretically and experimentally using observation data of historical tsunami from 1992 to 2018. The physical mechanisms leading to the lognormal distribution of tsunami runup heights along the coast are discussed, and its statistical moments are calculated. It is shown that the lognormal distribution describes well the measurements of tsunami characteristics over the past 30 years. Special attention is paid to the multi-source 2018 Palu–Sulawesi tsunami, which was generated by an earthquake with magnitude 7.5 and numerous subsequent landslides. It is shown that even in this special case the lognormal distribution is a rather good approximation.
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Dogan, Gozde Guney; Pelinovsky, Efim; Zaytsev, Andrey; Metin, Ayse Duha; Tarakcioglu, Gulizar Ozyurt & Yalciner, Ahmet Cevdet
[Vis alle 8 forfattere av denne artikkelen]
(2021).
Long wave generation and coastal amplification due to propagating atmospheric pressure disturbances.
Natural Hazards.
ISSN 0921-030X.
106(2),
s. 1195–1221.
doi:
10.1007/s11069-021-04625-9.
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Abstract Meteotsunamis are long waves generated by displacement of a water body due to atmospheric pressure disturbances that have similar spatial and temporal characteristics to landslide tsunamis. NAMI DANCE that solves the nonlinear shallow water equations is a widely used numerical model to simulate tsunami waves generated by seismic origin. Several validation studies showed that it is highly capable of representing the generation, propagation and nearshore amplification processes of tsunami waves, including inundation at complex topography and basin resonance. The new module of NAMI DANCE that uses the atmospheric pressure and wind forcing as the other inputs to simulate meteotsunami events is developed. In this paper, the analytical solution for the generation of ocean waves due to the propagating atmospheric pressure disturbance is obtained. The new version of the code called NAMI DANCE SUITE is validated by comparing its results with those from analytical solutions on the flat bathymetry. It is also shown that the governing equations for long wave generation by atmospheric pressure disturbances in narrow bays and channels can be written similar to the 1D case studied for tsunami generation and how it is integrated into the numerical model. The analytical solution of the linear shallow water model is defined, and results are compared with numerical solutions. A rectangular shaped flat bathymetry is used as the test domain to model the generation and propagation of ocean waves and the development of Proudman resonance due to moving atmospheric pressure disturbances. The simulation results with different ratios of pressure speed to ocean wave speed (Froude numbers) considering sub-critical, critical and super-critical conditions are presented. Fairly well agreements between analytical solutions and numerical solutions are obtained. Additionally, basins with triangular (lateral) and stepwise shelf (longitudinal) cross sections on different slopes are tested. The amplitudes of generated waves at different time steps in each simulation are presented with discussions considering the channel characteristics. These simulations present the capability of NAMI DANCE SUITE to model the effects of bathymetric conditions such as shelf slope and local bathymetry on wave amplification due to moving atmospheric pressure disturbances.
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Su, Pin-Tzu; Didenkulova, Ira & Jensen, Atle
(2024).
Transport of sinking debris by solitary waves on a beach.
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Su, Pin-Tzu; Didenkulova, Ira & Jensen, Atle
(2024).
Tsunami-induced boulder motion on a sandy slope.
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Kleidon, Axel; Messori, Gabriele; Roy, Somnath Baidya; Didenkulova, Irina & Zeng, Ning
(2023).
Editorial: Global warming is due to an enhanced greenhouse effect, and anthropogenic heat emissions currently play a negligible role at the global scale.
Earth System Dynamics (ESD).
ISSN 2190-4979.
14(1),
s. 241–242.
doi:
10.5194/esd-14-241-2023.
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Publisert
6. aug. 2020 09:50
- Sist endret
26. jan. 2025 21:17
