Spatially-averaged momentum fluxes and stresses in flows over mobile granular beds : a DNS-based study

Acknowledgements The authors gratefully acknowledge the Centre for Information Services and High Performance Computing (ZIH), Dresden, and the Jülich Supercomputing Centre (JSC) for providing computing time. The authors thank Markus Uhlmann and Clemens Chan-Braun for stimulating discussions on bed-load transport. Funding The present work was funded by the German Research Foundation (DFG) via the project [FR 1593/5-2] and was partly supported by the Engineering and Physical Sciences Research Council (EPSRC) UK, Grant [EP/G056404/1].Peer reviewedPublisher PD

Momentum balance in flows over mobile granular beds : application of double-averaging methodology to DNS data

The authors gratefully acknowledge the Centre for Information Services and High Performance Computing (ZIH), Dresden, and the Jülich Supercomputing Centre (JSC) for providing computing time. The authors thank Markus Uhlmann and Clemens Chan-Braun for stimulating discussions on bed-load transport.Peer reviewedPublisher PD

Simulation of the cavitating flow in a model oil hydraulic spool valve using different model approaches

The contribution compares results of Large Eddy Simulations of the cavitating flow in a model oil hydraulic spool valve using an Euler-Euler and a one-way coupled Euler- Lagrange model. The impact of the choice of the empirical constants in the Kunz cavitation model is demonstrated. Provided these are chosen appropriately the approach can yield reasonable agreement with the corresponding experiment. The one-way Euler-Lagrange model yields less agreement. It is demonstrated that this is due to the lack of realistic volumetric coupling, rarely accounted for in this type of method. First results of such an algorithm are presented featuring substantially more realism

Large Eddy Simulations for Dispersed bubbly Flows

In this paper we present detailed Euler-Euler Large Eddy Simulations (LES) of dispersed bubbly flow in a rectangular bubble column. The motivation of this study is to investigate potential of this approach for the prediction of bubbly flows, in terms of mean quantities. The set of physical models describing the momentum exchange between the phases was chosen according to previous experiences of the authors. Experimental data, Euler-Lagrange LES and unsteady Euler-Euler Reynolds-Averaged Navier-Stokes model are used for comparison. It was found that the presented modelling combination provides good agreement with experimental data for the mean flow and liquid velocity fluctuations. The energy spectrum made from the resolved velocity from Euler-Euler LES is presented and discussed