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Wave-induced bedload transport – a study of the southern Baltic coastal zone

Dudkowska A., Gic-Grusza G.

Geologos

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2017

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Vol. 23, No. 1

1--14

EN

The wave-induced bedload transport and spatial distribution of its magnitude in the southern Baltic coastal zone of Poland are estimated. The vicinity of Lubiatowo was selected as a representative part of the Polish coast. It was assumed that transport is a function of shear stress; alternative approaches, based on force balances and discharge relationships, were not considered in the present study. Four models were studied and compared over a wide range of bottom shear stress and wind-wave conditions. The set of models comprises classic theories that assume a simplified influence of turbulence on sediment transport (e.g., advocated by authors such as Du Boys, Meyer-Peter and Müller, Ribberink, Engelund and Hansen). It is shown that these models allow to estimate transport comparable to measured values under similar environmental conditions. A united general model for bedload transport is proposed, and a set of maps of wave bedload transport for various wind conditions in the study area is presented.

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Port of Gdańsk and Port of Gdynia’s exposure to threats resulting from storm extremes

Cieślikiewicz W., Dudkowska A., Gic-Grusza G.

Journal of Polish Safety and Reliability Association

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2016

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Vol. 7, No. 1

29--36

EN

This study is intended to make a first estimate of the exposure of the two Polish largest ports – Gdańsk and Gdynia, localized in the Gulf of Gdańsk – to threats from storm extremes. These ports are elements of the Polish critical infrastructure and presented analysis is one of the tasks related to critical infrastructure protection. Hypothetical extreme meteorological conditions have been defined based on 138-year NOAA data and assumed wave fields for those conditions have been generated. Using HIPOCAS project database the 21 extreme historical storms over the period 1958–2001 were selected to simulate realistic conditions in the vicinity of the ports. The highest significant wave height was found to be nearly 4 m in the vicinity of Port of Gdańsk and nearly 2 m in the vicinity of Port of Gdynia. A future intensification of these wave conditions should be considered due to the climate change and sea level rise.

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A note on the vertical distribution of momentum transport in water wavesa

Kołodko J., Gic-Grusza G.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 4

563--568

EN

In this paper, the classical problem of horizontal waveinduced momentum transport is analyzed once again. A new analytical approach has been employed to reveal the vertical variation of this transport in the Eulerian description. In mathematical terms, this variation is shown to have (after “smoothing out” the surface corrugation) the character of a generalized function (distribution) and is described by a classical function in the water depths and by an additional Dirac-delta-function component on the averaged free surface. In terms of physics, the considered variation consists of two entities: (i) a continuous distribution of the mean momentum transport flux density (tensorial radiation pressure) over the entire water column, and (ii) an additional momentum transport flux concentrated on the mean free surface level (tensorial radiation surface pressure). Simple analytical formulae describing this variation have been derived. This allowed a conventional expression to be derived, describing the depth-integrated excess of horizontal momentum flux due to the presence of waves (the so-called “radiation stress”), confirming to some extent the correctness of the whole analysis carried out. The results obtained may be important to the ocean dynamics, especially in view of their possible application in the field of hydrodynamics of wave-dominated coastal zones.