Two subsequent presentations on the 13th UnTRIM Workshop 2016 with the same title Efficient river modelling applying subgrid technology (UnTRIM2), the first part concerning concept and grids, presented by Regina Patzwahl, and the second part concerning results, presented by Jacek A. Jankowski. Continue reading
Tag Archives: fluvial flows
On the representation of bottom shear stress in z-layer models
F. Platzek, G.S. Stelling, J.A. Jankowski, R. Patzwahl
Abstract. Bottom friction plays an important role in modelling river flows. In three-dimensional (3D) models, the vertical discretization is commonly based on σ-layers or z-layers. In this paper we focus on a well-known problem encountered when applying z-layers: local truncation errors in the computation of bottom shear stress and near-bed turbulence along a sloping bottom as e.g. in the case of 3D river simulations. This problem stems from the ‘staircase’ representation of the bottom and results in difficulties in the computation of morphological changes. Continue reading
Very high resolution numerical modelling for inland waterway design
R. Patzwahl, J.A. Jankowski, T. Lege
Abstract. The paper discusses the advantages and disadvantages of numerical modelling of rivers with a grid of very high resolution using the new MPI version of UnTRIM as the computational engine. The main aim of the investigation is to assess the economy of this approach taking especially into account the effort required for the mesh generation and its modification, which is usually laborious in the case of coarser meshes requiring exact reproduction of structure lines defining the flow. Continue reading
UnTRIM applications for fluvial flows
Jacek A. Jankowski. UnTRIM applications for fluvial flows, 1st UnTRIM Workshop, Verona, 7-9 June 2004.
Attracted by the proven and excellent mathematical properties of the scheme and the ongoing OpenMP parallelisation of the UnTRIM code, BAW Karlsruhe has initiated an internal investigation to assess the feasibility of the freshly developed code for the engineering applications concerning river flows. Continue reading