Tag Archives: numerical modelling

Parametrization and evaluation of marine environmental impacts produced by deep-sea manganese nodule mining

Oebius, H.U., Becker, H.J., Rolinski, S., Jankowski, J.A.

Abstract. The evaluation of marine environmental impacts resulting from the exploitation of marine resources requires the numerical description, parametrization, and modelling of such processes in order to be able to transfer, compare, and forecast the effects of anthropogenic activities in the deep sea. One of the controversial effects is the formation and behaviour of sediment clouds as a consequence of anthropogenic activities on the seafloor. Continue reading

The mesoscale sediment transport due to technical activities in the deep sea

J.A. Jankowski and W. Zielke

Abstract. This paper presents a mesoscale model for sediment transport in the deep sea resulting from technical activities such as manganese nodule mining. The model includes the temporal variability of ambient currents, the modification of the water density due to suspended sediments (density driven flow), bottom boundary-layer effects, and the influence of flocculation on the sediment settling velocity. It yields the three-dimensional sediment concentration and the bottom blanketing for time periods of up to a few weeks in areas of up to a few hundred square kilometers. The model also allows simulation of the mobilization, sorption and the transport of heavy metals. Continue reading

A threedimensional non-hydrostatic model for free surface flows – development, verification and limitations

Holger Weilbeer, Jacek A. Jankowski and Werner Zielke

Abstract. The theoretical background of a new finite-element non-hydrostatic model for simulation of free surface flows based on the fractional step method and pressure decomposition is presented. Continue reading

A non-hydrostatic model for free surface flows

Jacek A. Jankowski

PhD thesis Abstract

An algorithm for solution of three-dimensional Navier-Stokes equations for incompressible free surface flows is developed. A decoupled algorithm based on the fractional step (operator-splitting) technique is applied. The solution is obtained in subsequent stages treating equations split into parts having well-defined mathematical properties, so that the most adequate methods for a given differential operator type can be used. The decoupled algorithm structure, which does not use the continuity equation explicitly, allows application of equal-order linear interpolation functions for all variables. The applied reference element type, a prism with six nodes and linear interpolation functions, is a compromise between the exactness of the interpolation, model complexity and computational cost. The finite difference method is applied for the time discretisation and the computational domain variability is taken into account by a standard sigma-mesh structure which is well suited to most geophysical applications. Continue reading

Ein nicht-hydrostatisches Modell für Strömungen mit freier Oberfläche

Ein nicht-hydrostatisches Modell für Strömungen mit freier Oberfläche, Promotionsvortrag, 12. November 1998, Institut für Strömungsmechanik und Elektronisches Rechnen im Bauwesen der Universität Hannover. Continue reading