Effect of Wall Roughness Seen by Particles in Turbulent Channel and Pipe Flows

In the present contribution it is shown in the context of large–eddy simulation (LES) and a Lagrangian treatment of the disperse phase that it is possible to considerably improve the particle statistics in turbulent channel and pipe flows by adopting a recently published wall roughness model for the solid phase. First, the model presented by Breuer etal.(Int J Multiphase Flow 43:157–175, 2012) is evaluated by means of the experiments conducted for a turbulent channel flow by Kussin(Experimentelle Studien zur Partikelbewegung und Turbulenzmodifikation in einem horizontalen Kanal bei unterschiedlichen Wandrauhigkeiten. Ph.D. thesis, Martin–Luther–Universität Halle–Wittenberg, Germany, 2004) and Kussin and Sommerfeld(Exp Fluids 33:143–159, 2002). As a second test case the experiments of Borèe and Caraman(Phys Fluids 17:055108–1–055108–9, 2005) carried out for a turbulent pipe flow were used. For both setups involving rough walls good agreement between experiment and simulation is achieved by considering the effect of the wall roughness on the particle motion. Especially the latter configuration is the precondition for an improved simulation of the complex particle–laden turbulent flow in a combustion chamber reported in the last issue (Breuer and Alletto, High Performance Computing in Science and Engineering ’11. Springer, Berlin/Heidelberg, 2012) and in Alletto and Breuer(Int J Multiphase Flow 45: 70–90, 2012) and Breuer and Alletto(Int J Heat Fluid Flow 35:2–12, 2012).