To simulate dune development, a model based on the two-dimensional vertical shallow water equations is applied to flume conditions. Realistic bedform behaviour of dunes with gentle slopes is obtained: dunes grow in amplitude, develop into asymmetric features and migrate. Due to a constant eddy viscosity in the model, flowseparation cannot be treated explicitly. Therefore, a parameterization for flowseparation is proposed, based on flume data. A parameterization is derived for the separating streamline, which is the upper boundary of the flow separation zone, and which can be used as bed level for flow computations. The shape of the flow separation zone is found to be independent of flow conditions, and is related to the height and local bed angle at the separation point, and to the angle of the separating streamline at the reattachment point. The parameterization is in reasonable agreement with flume data.
|Title of host publication||River Coastal and Estuarine Morphodynamics: RCEM 2005, Vol II, 4-7 October 2005, Urbana, Illinois, USA|
|Editors||G. Parker, M.H. García|
|Place of Publication||London|
|Publisher||Balkema / Taylor&Francis|
|Publication status||Published - 4 Oct 2005|
Paarlberg, A., Dohmen-Janssen, C. M., Hulscher, S. J. M. H., & Termes, A. P. P. (2005). A parameterization for flow separation in a river dune development model. In G. Parker, & M. H. García (Eds.), River Coastal and Estuarine Morphodynamics: RCEM 2005, Vol II, 4-7 October 2005, Urbana, Illinois, USA (pp. 883-895). London: Balkema / Taylor&Francis.