Computations of forces on, and particle orbits around, horizontal cylinders under steep waves     

J. Skourup  I.G. Jonsson 《Ocean Engineering》1992,19(6)

A numerical method, based on a boundary integral equation combined with a non-linear time stepping procedure for the free water surface, is developed for simulations of the interaction between highly non-linear water waves and submerged horizontal cylinders. The method is based on potential theory, and the omission of viscous effects restricts the wave-structure interaction computations to low Keulegan-Carpenter numbers where inertia forces are dominant. The numerical scheme is verified by computations with a steep wave of exact form during several wave periods, and by computations of a breaking wave. A new method for tracing the orbits of water particles in the fluid domain is developed, and the influence from submerged structures on the orbits is visualized through several computational examples. The wave forces on submerged structures are computed and are found to correspond well with other computed results for low Keulegan-Carpenter numbers.  相似文献   

Cultured Atlantic salmon in nature: a review of their ecology and interaction with wild fish   总被引：4，自引：0，他引：4  

Jonsson  Bror; Jonsson  Nina 《ICES Journal of Marine Science》2006,63(7):1162-1181

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CCN measurements during ACE‐2 and their relationship to cloud microphysical properties     

P. Y. Chuang  D. R. Collins  H. Pawlowska  J. R. Snider  H. H. Jonsson  J. L. Brenguier  Richard C. Flagan  John H. Seinfeld 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):843-867

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CORRESPONDENCE     

H. J. Andrews.  Patrik  Mogensen P. O. Fagerholm 《The Photogrammetric Record》1955,1(5):76-77

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Longwave incoming radiation in the Tropics: results from field work in three African cities     

P. Jonsson  I. Eliasson  B. Holmer  C. S. B. Grimmond 《Theoretical and Applied Climatology》2006,85(3-4):185-201

Summary This study investigates differences in longwave incoming radiation (L↓) within and between three African cities, Dar es Salaam (Tanzania), Ouagadougou (Burkina Faso), and Gaborone (Botswana), during the dry season, and evaluates the performance of a model to simulate these fluxes. In each city, direct observations of L↓, shortwave incoming radiation (K↓), air temperature, air humidity, and total suspended particle (TSP) concentration for three land uses (CBD, green residential, and traditional residential) were taken. The observed L↓ flux decreases with increasing latitude, and temperature becomes an increasingly important factor in governing L↓ variations further from the Equator. Humidity, as well as particle loading, differs significantly between the three cities. Differences between observed and modelled ɛ_sky for rural stations near all cities showed a clear diurnal variation, with maximum differences of 0.08 between day and night. This diurnal difference was incorporated in the model and, for urban areas the model overestimates L↓ by around 25 Wm⁻². However, this model performs equally well regardless of the land use considered in any of the cities. The residual (difference between observed and modelled urban L↓) did not show any correlation with particulate pollution. However, the difference between observed and calculated ɛ_sky is around 0.05 higher in Ouagadougou compared to the other cities, likely due to the heavy dust load observed here. It is concluded that tropical urban longwave radiation is not dramatically different from the mid latitudes.  相似文献   

Salinity and Chlorophyll a as Performance Measures to Rehabilitate a Mangrove-Dominated Deltaic Coastal Region: the Ci��naga Grande de Santa Marta�CPajarales Lagoon Complex, Colombia     

Victor H. Rivera-Monroy  Robert R. Twilley  J. Ernesto Mancera-Pineda  Christopher J. Madden  Ariel Alcantara-Eguren  E. Barry Moser  Bror F. Jonsson  Edward Casta?eda-Moya  Oscar Casas-Monroy  Paola Reyes-Forero  Jorge Restrepo 《Estuaries and Coasts》2011,34(1):1-19

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Phosphorus release from coastal Baltic Sea sediments as estimated from sediment profiles   总被引：1，自引：0，他引：1  

E. Rydin  J.M. Malmaeus  O.M. Karlsson  P. Jonsson 《Estuarine, Coastal and Shelf Science》2011

We used the decline in total phosphorus (P) concentration with depth in sediment profiles from the North-western Baltic Proper coastal zone to calculate the site-specific amount of sediment P eventually to be released to the water column: The potentially mobile P. P fractionation revealed that iron bound P dominated the potentially mobile P at sites with oxic surface sediment layers. Organic P forms were also a major constituent of the potentially mobile P pool. We determined that 1–7 g P/m² were potentially mobile at our sites, and the turnover time of this P pool was considered short, i.e., less than a decade. To determine long-term average P fluxes to and from the surface sediment layer, we first multiplied the constant and relatively low P concentration in deeper sediment layers with the sediment accumulation rate to gain the P burial rate. Then the average total P concentration in settling matter was multiplied with the sediment accumulation rate to estimate the depositional P flux at each site. The difference between the depositional and burial rates represents the long-term average release rate of sediment P and varied between 1.0 and 2.7 g P/m² yr among our sites. These rates are at the same order of magnitude as values reported from other areas of the Baltic Sea, and constitute a major source of P to the water column.  相似文献   

sunrise: polychromatic dust radiative transfer in arbitrary geometries     

Patrik Jonsson 《Monthly notices of the Royal Astronomical Society》2006,372(1):2-20

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Seismic strengthening of existing RC buildings with external cross-laminated timber (CLT) walls hosting an integrated energetic and architectural renovation     

Badini  Lorenzo  Ott  Stephan  Aondio  Patrik  Winter  Stefan 《Bulletin of Earthquake Engineering》2022,20(11):5963-6006

Bulletin of Earthquake Engineering - In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such...  相似文献   

Groundwater flow modeling of periods with periglacial and glacial climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark,Sweden     

Patrik Vidstrand  Sven Follin  Jan-Olof Selroos  Jens-Ove Näslund 《Hydrogeology Journal》2014,22(6):1251-1267

The impact of periglacial and glacial climate conditions on groundwater flow in fractured crystalline rock is studied by means of groundwater flow modeling of the Forsmark site, which was recently proposed as a repository site for the disposal of spent high-level nuclear fuel in Sweden. The employed model uses a thermal-hydraulically coupled approach for permafrost modeling and discusses changes in groundwater flow implied by the climate conditions found over northern Europe at different times during the last glacial cycle (Weichselian glaciation). It is concluded that discharge of particles released at repository depth occurs very close to the ice-sheet margin in the absence of permafrost. If permafrost is included, the greater part discharges into taliks in the periglacial area. During a glacial cycle, hydraulic gradients at repository depth reach their maximum values when the ice-sheet margin passes over the site; at this time, also, the interface between fresh and saline waters is distorted the most. The combined effect of advances and retreats during several glaciations has not been studied in the present work; however, the results indicate that hydrochemical conditions at depth in the groundwater flow model are almost restored after a single event of ice-sheet advance and retreat.  相似文献