Literature Review Notes - 2004

Short Description of Turbulence Modelling. If I have this right, Boussinesq hypothesis uses the turbulent eddy viscosity (v _t)whereby the molecular viscosity for laminar flows is replaced by the v _t. Prandtl introduced the additional concept of the mixing length and boundary layer. Then we get into the more complex models k-e, Smagorinsky etc.

Relevant paper to current research.

Lane, S. N., Hardy, R. J., Elliott, L., & Ingham, D. B. (2002). High-resolution numerical modelling of three-dimensional flows over complex river bed topography. Hydrological Processes, 16(11), 2261-2272. doi: 10.1002/hyp.5034.

Excellent description on the issues with trying to model dynamic bed forms. They use a porosity model to model the bed forms.

Another significant paper – describing the development of a 1-D hydrodynamic model using the complete momentum equation:

Cao, Z., Pender, G., Wallis, S., & Carling, P. (2004). Computational Dam-Break Hydraulics over Erodible Sediment Bed. Journal of Hydraulic Engineering, 130(7), 689. doi: 10.1061/(ASCE)0733-9429(2004)130:7(689).

In the context of computational study of dam-break hydraulics,several basic observations are warranted. First, it is recognized that the flow, sediment transport, and morphological evolution can be strongly coupled to each other, the rate of bed deformation being considerable compared to that of flow evolution. Therefore a coupled modeling strategy with the use of the complete conser- vation equations and synchronous solution procedure is essential, in contrast to decoupled modeling using an asynchronous solution of simplified conservation equations (Cao et al. 2002). In this connection, the models of Ferreira and Leal (1998) and Yang and Greimann (1999) are problematic because of the simplified con- servation equations used.

Dam-break flows over mobile beds can provoke very active sediment exchange between the water column and the bed, and also produce a sharp spatial gradient of concentration, which must be incorporated in the momentum equation. Otherwise significant errors result (Fig. 11), in contrast to Brufau et al. (2000) for debris flows. Previous models for dam-break problems can be improved by using the complete, instead of simplified, momentum equations (e.g.,CADAM 1998, 1999a,b).