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The main stages in the development of the Pechora Sea are discussed. It is established that, during the high sea level stand corresponding to the warmest epoch of the Mikulino Interglacial, the Pechora Sea represented a more spacious, as compared with its present-day size, basin owing to the flooded valleys of river lower reaches. No sea in its present-day configuration existed during the last (Valdai) glaciation. At that time, the sea could have occupied only a narrow area along the southern coast of Novaya Zemlya, where marine sedimentation was in progress during the Late Pleistocene and Holocene. During the glaciation and postglacial time, the dried bottom of the former Pechora Sea accumulated large volumes of sand that are now concentrated largely in the accretion structures along its southern coast. In the current century, changes will occur mainly in the coastal zone of the Russkii Zavorot Peninsula, Pesyakov Island, the Varandei Settlement area, and the Medynskii Zavorot Peninsula, where a shoreline retreat for a distance of 0.5 km is expected. 相似文献
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P. Salinas D. Pavlidis Z. Xie H. Osman C. C. Pain M. D. Jackson 《Computational Geosciences》2018,22(5):1389-1401
Flows of multiple fluid phases are common in many subsurface reservoirs. Numerical simulation of these flows can be challenging and computationally expensive. Dynamic adaptive mesh optimisation and related approaches, such as adaptive grid refinement can increase solution accuracy at reduced computational cost. However, in models or parts of the model domain, where the local Courant number is large, the solution may propagate beyond the region in which the mesh is refined, resulting in reduced solution accuracy, which can never be recovered. A methodology is presented here to modify the mesh within the non-linear solver. The method allows efficient application of dynamic mesh adaptivity techniques even with high Courant numbers. These high Courant numbers may not be desired but a consequence of the heterogeneity of the domain. Therefore, the method presented can be considered as a more robust and accurate version of the standard dynamic mesh adaptivity techniques. 相似文献
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Distribution of clay minerals in surface sediments from the eastern Barents and south-western Kara seas 总被引：2，自引：0，他引：2
D. Nürnberg M. A. Levitan J. A. Pavlidis E. S. Shelekhova 《International Journal of Earth Sciences》1995,84(3):665-682
Surface samples from the eastern Barents and south-western Kara seas have been analysed for clay mineralogy. Transport paths, the role of regional sources and local bedrock outcrops and the influence of hydrodynamic and glacigenous processes for clay distribution on the shelves are discussed in relation to central Arctic Ocean deep sea and sea ice sediments. Franz Josef Land and Novaya Zemlya show significantly different clay mineral associations. Although smectite concentrations are fairly high, Franz Josef Land can be excluded as a source for central Arctic sea ice sediments, which are relatively rich in smectite. In the Kara Sea, smectite concentrations in coastal sediments surpass even the Franz Josef Land concentrations. The large cyclonic gyre in the eastern Barents Sea between Novaya Zemlya and Franz Josef Land, which serves as a mixing zone between Arctic and North Atlantic water, is apparently reflected within the smectite distribution pattern. With the exception of Franz Josef Land, the area of investigation is typically low in kaolinite. In particular, coastal areas and areas north of Novaya Zemlya, influenced by the inflow of Arctic waters, show the lowest kaolinite concentrations. A high kaolinite occurrence within the Nansen Basin is most probably related to Franz Josef Land and emphasizes the importance of long-range downslope transport of sediments across the continental slope. The surface water circulation pattern in close interaction with local outcrops onshore Novaya Zemlya and locally restricted occurrences within the eastern Barents Sea significantly alter the illite dispersal pattern. Illite concentrations are lowest around Franz Josef Land. Chlorite is generally low in the area of investigation. Submarine outcrops and important chlorite occurrences onshore Novaya Zemlya bias its distribution pattern. 相似文献
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Vir&#; Axelle Xiang Jiansheng Milthaler Frank Farrell Patrick Emmet Piggott Matthew David Latham John-Paul Pavlidis Dimitrios Pain Christopher Charles 《Ocean Dynamics》2012,62(10):1487-1501
Fluid–structure interactions are modelled by coupling the finite element fluid/ocean model ‘Fluidity-ICOM’ with a combined finite–discrete element solid model ‘Y3D’. Because separate meshes are used for the fluids and solids, the present method is flexible in terms of discretisation schemes used for each material. Also, it can tackle multiple solids impacting on one another, without having ill-posed problems in the resolution of the fluid’s equations. Importantly, the proposed approach ensures that Newton’s third law is satisfied at the discrete level. This is done by first computing the action–reaction force on a supermesh, i.e. a function superspace of the fluid and solid meshes, and then projecting it to both meshes to use it as a source term in the fluid and solid equations. This paper demonstrates the properties of spatial conservation and accuracy of the method for a sphere immersed in a fluid, with prescribed fluid and solid velocities. While spatial conservation is shown to be independent of the mesh resolutions, accuracy requires fine resolutions in both fluid and solid meshes. It is further highlighted that unstructured meshes adapted to the solid concentration field reduce the numerical errors, in comparison with uniformly structured meshes with the same number of elements. The method is verified on flow past a falling sphere. Its potential for ocean applications is further shown through the simulation of vortex-induced vibrations of two cylinders and the flow past two flexible fibres.
相似文献5.
Axelle Viré Jiansheng Xiang Frank Milthaler Patrick Emmet Farrell Matthew David Piggott John-Paul Latham Dimitrios Pavlidis Christopher Charles Pain 《Ocean Dynamics》2012,62(10-12):1487-1501
Fluid–structure interactions are modelled by coupling the finite element fluid/ocean model ‘Fluidity-ICOM’ with a combined finite–discrete element solid model ‘Y3D’. Because separate meshes are used for the fluids and solids, the present method is flexible in terms of discretisation schemes used for each material. Also, it can tackle multiple solids impacting on one another, without having ill-posed problems in the resolution of the fluid’s equations. Importantly, the proposed approach ensures that Newton’s third law is satisfied at the discrete level. This is done by first computing the action–reaction force on a supermesh, i.e. a function superspace of the fluid and solid meshes, and then projecting it to both meshes to use it as a source term in the fluid and solid equations. This paper demonstrates the properties of spatial conservation and accuracy of the method for a sphere immersed in a fluid, with prescribed fluid and solid velocities. While spatial conservation is shown to be independent of the mesh resolutions, accuracy requires fine resolutions in both fluid and solid meshes. It is further highlighted that unstructured meshes adapted to the solid concentration field reduce the numerical errors, in comparison with uniformly structured meshes with the same number of elements. The method is verified on flow past a falling sphere. Its potential for ocean applications is further shown through the simulation of vortex-induced vibrations of two cylinders and the flow past two flexible fibres. 相似文献
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Anisotropic Mesh Adaptivity and Control Volume Finite Element Methods for Numerical Simulation of Multiphase Flow in Porous Media 总被引：1，自引：1，他引：0
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D. Pavlidis G. J. Gorman J. L. M. A. Gomes C. C. Pain H. ApSimon 《Boundary-Layer Meteorology》2010,136(2):285-299
The computational fluid dynamics code Fluidity, with anisotropic mesh adaptivity, is used as a multi-scale obstacle-accommodating
meteorological model. A novel method for generating realistic inlet boundary conditions based on the view of turbulence as
a superposition of synthetic eddies is adopted. It is able to reproduce prescribed first-order and second-order one-point
statistics and turbulence length scales. The aim is to simulate an urban boundary layer. The model is validated against two
standard benchmark tests: a plane channel flow numerical simulation and a flow past a cube physical simulation. The performed
large-eddy simulations are in good agreement with both reference models giving confidence that the model can be used to successfully
simulate urban atmospheric flows. 相似文献
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Yu. A. Pavlidis I. O. Leont’ev S. L. Nikiforov F. Rahold M. N. Grigor’ev S. R. Razumov A. A. Vasil’ev 《Oceanology》2007,47(1):116-126
Principal regularities of the evolution of the Arctic coasts of Eurasia in the 21st century related to the climate warming and sea level rise are assessed. It is stated that the most significant changes may be expected in the most ice-covered seas of the Arctic Ocean, where the area of the ice cover may significantly decrease while the duration of the ice-free periods will grow. Thermoabrasive coasts will be the most subjected to the changes; the rate of their recession will increase 1.5–2.5 fold. The further development of accumulative coasts in the Arctic seas will proceed against the background of a transgression; meanwhile, in the 21st century, one can expect no catastrophic changes such as washing away of coastal accumulative features. 相似文献
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S. L. Nikiforov Yu A. Pavlidis V. Rachold M. N. Grigoryev F. M. Rivkin N. V. Ivanova M. M. Koreisha 《Geo-Marine Letters》2005,25(2-3):89-97
Arctic coastal evolution is the result of interactions between exogenic and endogenic processes. In the arctic region, this evolution differs from that in other areas of the worlds oceans as a result of interactions between modern wave and ice factors, and the influences of glaciations and large-scale sea level changes in the past. Geologic structure, origin and development determine contemporary relief morphology. Morphology appears to be the most significant relief characteristic, but it is controlled by a set of interactive processes active over long periods. Our approach, in which a multitude of interacting factors are simultaneously analyzed and determined, could be called morphogenetic. We consider marine coasts and offshore zones (shelf) as a unit, and providing a general explanation for their evolution. The classification presented here is based upon the general approach given in the Science and Implementation Plan of Arctic Coastal Dynamics (ACD), a project of the International Arctic Science Committee and the International Permafrost Association. Our classification extends beyond the morphological ACD classification to include a morphogenetic classification. 相似文献
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