Selection of modes from a shallow-water noise field by single bottom hydrophones for passive tomography purposes

2014 ◽  
Vol 60 (6) ◽  
pp. 647-656 ◽  
Author(s):  
V. A. Burov ◽  
A. V. Grinyuk ◽  
V. N. Kravchenko ◽  
P. Yu. Mukhanov ◽  
S. N. Sergeev ◽  
...  
Keyword(s):  
Shallow Water ◽  
Noise Field ◽  
Passive Tomography ◽  
Selection Of

scholarly journals Ship Motions in Shallow Water As the Base for a Probabilistic Approach Policy

2008 ◽  
Author(s):  
Marc Vantorre ◽  
Erik Laforce ◽  
Katrien Eloot ◽  
Jan Richter ◽  
Jeroen Verwilligen ◽  
...  
Keyword(s):  
Shallow Water ◽  
Probabilistic Approach ◽  
Ship Motions ◽  
Wave Spectra ◽  
Fluid Mud ◽  
Response Functions ◽  
Regular Waves ◽  
Directional Wave ◽  
Probabilistic Criteria ◽  
Selection Of

A calculation tool has been developed for determining tidal windows for deep-drafted ships approaching and leaving the Belgian harbors according to probabilistic criteria. The calculations are based on a database containing response functions for the vertical motions in waves and squat data for a selection of representative ships. The database contains both results of model tests carried out in the Towing tank for maneuvers in shallow water – co-operation Flanders Hydraulics Research & Ghent University in Antwerp (Belgium), as well as calculated values. During the experiments, draft, trim, under keel clearance (7 to 20% of draft) and speed have been varied. The tests were performed in regular waves with lengths which are small compared to ship length, and in wave spectra that are typical for the Belgian coastal area. For given input data (ship characteristics, speed, tide, directional wave spectra, bottom, trajectory, current, departure time), the tool calculates the probability of bottom touch during the transit, so that a tidal window can be determined. Other restrictions, such as penetration into fluid mud layers and current, are taken into account as well.

Desquamatia and related atrypid brachiopods from the Frasnian (Upper Devonian) of Bergisches Land, GermanyThis article is one of a selection of papers published in this Special Issue on the theme The dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.

2008 ◽  
Vol 45 (2) ◽  
pp. 121-134
Author(s):  
Xueping Ma ◽  
Volker Ebbighausen ◽  
R. Thomas Becker
Keyword(s):  
New Species ◽  
Shallow Water ◽  
Upper Devonian ◽  
Rhine River ◽  
Special Issue ◽  
Rhenish Massif ◽  
Dental Cavities ◽  
A New Species ◽  
Selection Of

Tropical shallow-water deposits of the Refrath Formation (topmost Lower to lower part of Middle Frasnian) of the Bergisch Gladbach area (Rhenish Massif, Germany) yielded diverse, well-preserved shelly faunas. New collections show that there are in total over 30 brachiopod species, of which the Atrypida, Rhynchonellida, Spiriferida, and Athyridida orders are the most dominant groups. Serial transverse sections show that Pseudoatrypa schroeteri possesses small dental cavities, and their spiralia have a whorl number ranging from 12–13 in ca. 29–30 mm wide specimens to 15–16 in ca. 32–33 mm wide specimens. Desquamatia (Seratrypa) pectinata has slightly more numerous spiralial whorls, from 14–15 in ca. 27 mm wide specimens to 18 in ca. 35 mm wide specimens. A new species, Desquamatia (Seratrypa) refrathensis , is described based on material from the Refrath Formation in Refrath, near Köln (Cologne), east of the Rhine River, Germany. It includes finely ribbed, longer than wide, moderate- to large-sized shells of Desquamatia , which possess tiny dental cavities to nuclei and 20–21 spiralial whorls in ca. 30 mm wide and long specimens.

Noise Field in Shallow Water

2011 ◽  
pp. 363-395
Author(s):  
Boris Katsnelson ◽  
Valery Petnikov ◽  
James Lynch
Keyword(s):  
Shallow Water ◽  
Noise Field

scholarly journals Analytical Treatment of the Generalized Hirota-Satsuma-Ito Equation Arising in Shallow Water Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-26
Author(s):  
Fan Yong-Yan ◽  
Jalil Manafian ◽  
Syed Maqsood Zia ◽  
Dinh Tran Ngoc Huy ◽  
Trung-Hieu Le
Keyword(s):  
Shallow Water ◽  
Water Waves ◽  
Bilinear Operator ◽  
Shallow Water Waves ◽  
Analytical Treatment ◽  
Kink Wave ◽  
Physical Phenomena ◽  
Hirota Bilinear ◽  
Ito Equation ◽  
Selection Of

In the current study, an analytical treatment is studied starting from the 2 + 1 -dimensional generalized Hirota-Satsuma-Ito (HSI) equation. Based on the equation, we first establish the evolution equation and obtain rational function solutions by means of the bilinear form with the help of the Hirota bilinear operator. Then, by the suggested method, the periodic, cross-kink wave solutions are also obtained. Also, the semi-inverse variational principle (SIVP) will be utilized for the generalized HSI equation. Two major cases were investigated from two different techniques. Moreover, the improved tan χ ξ method on the generalized Hirota-Satsuma-Ito equation is probed. The 3D, density, and contour graphs illustrating some instances of got solutions have been demonstrated from a selection of some suitable parameters. The existing conditions are handled to discuss the available got solutions. The current work is extensively utilized to report plenty of attractive physical phenomena in the areas of shallow water waves and so on.

scholarly journals The Number of Required Observations in Data Assimilation for a Shallow-Water Flow

2013 ◽  
Vol 141 (7) ◽  
pp. 2502-2518 ◽  
Author(s):  
William G. Whartenby ◽  
John C. Quinn ◽  
Henry D. I. Abarbanel
Keyword(s):  
Data Assimilation ◽  
Shallow Water ◽  
Water Flow ◽  
Correct Selection ◽  
Accurate Estimation ◽  
Integration Scheme ◽  
Model Output ◽  
Shallow Water Flow ◽  
Observation Window ◽  
Selection Of

Abstract The authors consider statistical ensemble data assimilation for a one-layer shallow-water equation in a twin experiment: data are generated by an N × N enstrophy-conserving grid integration scheme along with an Ekman vertical velocity at the bottom of an Ekman layer driving the flow and Rayleigh and eddy viscosity dissipation damping the flow. Data are generated for N = 16 and the chaotic flow that results is analyzed. This analysis is performed in a path-integral formulation of the data assimilation problem. These path integrals are estimated by a Monte Carlo method using a Metropolis Hastings algorithm. The authors' concentration is on the number of measurements Lc that must be assimilated by the model to allow accurate estimation of the full state of the model at the end of an observation window. It is found that for this shallow-water flow approximately 70% of the full set of state variables must be observed to accomplish either goal. The number of required observations is determined by examining the number needed to synchronize the observed data Lc and the model output when L data streams are assimilated by the model. Synchronization occurs when and the correct selection of which data are observed is made. If the number of observations is too small, so synchronization does not occur, or the selection of observations does not lead to synchronization of the data with the model output, state estimates during and at the end of the observation window and predictions beyond the observation window are inaccurate.

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