Mathematical Model SEDIMORPH

Short Description

The mathematical model SediMorph is a morphodynamic model which simulates the physical processes in the soil under surface waters. To do this the mass movements of the different grain classes according to bed load and suspended load transport and the pore water are balanced, respectively.

SediMorph is able to work on unstructured orthogonal grids (UOG). The modelling domain is covered by a grid consisting of a set of non-overlapping convex polygons, usually either triangles or quadrilaterals. The grid is said to be an unstructured orthogonal grid if within each polygon a point (hereafter called a center) can be identified in such a way that the segment joining the center of two adjacent polygons and the side shared by the two polygons, have a non-empty intersection and are orthogonal to each other. The vertical co-ordinate is resolved by horizontal layers with having unequal depths.

Physical processes

SediMorph takes into account the following processes:

• the variation of the grain size distribution in space and time,
• the spatial variation of bed forms
• the spatial variation of the bottom roughness resulting from grain and form roughness;
• the prediction od dunes and the pore water content
• the variation of the bed shear stress in space and time, resulting from variations of the bed roughness and the overlying currents,
• bed shear stresses resulting from waves,
• the erodibility of the bed sediments as a function of the pore water content,
• the calculation of the erosion rates;
• the calculation of the bed load transport rates for each fraction;
• the interface for the suspended sediment transport simulation to a hydrodynamic transport module,
• the simulation of the morphodynamics (Change of the water depths in space and time) as a result of bed load and suspended load transport

Simulation results

Synoptic results for:

• the distribution of the sediment fractions
• the mean grain diameter
• the grain roughness
• the pore water content
• the dune heights and lengths
• the ripple heights and lengths
• the transport capacities of every sediment fraction
• the transport rates of every sediment fraction
• the erosion rates of every sediment fraction
• the deposition rates of every sediment fraction

Publications

1. Malcherek, A. and Putzar, B. (2003). The Prediction of Dunes and Their Related Roughness in Estuarine Morphological Models. 8th Int. Conference on Estuarine and Coastal Modeling, Monterey, CA.
2. Malcherek, A. and Piechotta, F. (2004). Investigations on the Porosity as a Parameter for Sediment Erodibility. 9th Int. Symp. River Sedimentation, Vol. III, pp. 1913-1918.
3. Knoch, D. and Malcherek, A. (2005). The influence of waves on the sediment composition in a tidal bay. 9th Int. Conference on Estuarine and Coastal Modeling, Charlston.

Standard Validation document

A. Malcherek, F. Piechotta, D. Knoch Mathematical Module SediMorph - Standard Validation Document Version 1.1, Technical Report, Bundesanstalt fuer Wasserbau, 2005.

A PDF-version is freely available for download:

• (ca. 2.5 MB) SEDIMORPH Validation document

User Group (in alphabetical order)

• Bundesanstalt fuer Wasserbau;
• Professur fuer Hydromechanik und Wasserbau am Institut fuer Wasserwesen, Universitaet der Bundeswehr, Muenchen.

BAW-specific informations

Simulation

Actually the SEDIMORPH model can be used as a stand-alone postprocessor UNS, as well as directly coupled to the two-dimensional mathematical model TELEMAC-2D or the three-dimensional mathematical model UNTRIM for hydrodynamics and transport processes.

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