Tag Archives: free surface flows

Accurate vertical profiles of turbulent flow in z-layer models

F.W. Platzek, G.S. Stelling, J.A. Jankowski and J.D. Pietrzak

Abstract. Three-dimensional hydrodynamic z-layer models, which are used for simulating the flow in rivers, estuaries, and oceans, suffer from an inaccurate and often discontinuous bottom shear stress representation, due to the staircase bottom. We analyze the governing equations and clearly show the cause of the inaccuracies. Based on the analysis, we present a new method that significantly reduces the errors and the grid dependency of the results. Continue reading →

Potential der Intel Many Integrated Core Architektur für die Flussmodellierung — Codes UnTRIM und Telemac

Jacek A. Jankowski

This technical report (in German) concerns the assessment of porting feasibility of codes UnTRIM2 and Telemac to the Intel Xeon Phi, i.e. MIC (Many Integrated Cores) architecture. German abstract follows. Continue reading →

Adaptierung und Erweiterung von Casulli-Algorithmen für Parallelrechner mit Hardware-Beschleunigung und zur Anwendung von konservativen Advektionsverfahren

Jacek A. Jankowski

BAW internal R&D-project report, 2010-2012.

Abstract: The aim of the R&D-project is development and application of new programming paradigms in high performance computing through the adaptation of Casulli algorithms for arriving parallel computer architectures with hardware acceleration. Additionally, the existing advection schemes should be adapted for all flow regimes. Continue reading →

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 →

Bringing the principal 2Dxy scheme to a GPU

Jacek A. Jankowski. Bringing the principal 2Dxy scheme to a GPU, 8th UnTRIM Workshop, Trento, 9-11 May 2011.

The first part of the presentation concerns the process of finding an optimal GPU porting method for the principal two-dimensional, vertically integrated semi-implicit scheme for general free surface flows. Continue reading →