Rismo2D is a hydrodynamic numerical computer program to solve for the depth-averaged shallow water equations by means of the Finite Element Method. Rismo2D was developed during a research project funded by the German Research Foundation (DFG) at the Institute of Hydraulic Engineering and Water Resources Management - Aachen University:

The development of a numerical computational method
for near-natural streams
DFG-Project Ro 365 / 31

The final report of the project is available in German language:
Rouvé,G. & M.Schröder (1994): "Die Entwicklung eines mathematisch-numerischen Verfahrens zur Berechnung naturnaher Fließgewässer"; Abschlussbericht zum DFG-Projekt Ro 365 /31; korr. PDF-Version 12/2004

The DFG-Project has lasted from 1986 to 1994 and has produced also detailed experimental data from the flow in an idealized meandering channel with inundated flood plains (extent of the model: about 3 x 15 m). During the last two years the research work focused on the development of a three-dimensional computer program (Rismo3D).

The program Rismo2D computes the water elevation and the depth-averaged velocity for stationary or instationary streams. Based on a Finite Element discretization the computation can be carried out for arbitrary watercourses with complex geometrical and hydraulical boundary conditions.

Different laws may be used to account for bottom roughness. The friction of non-submerged flood plain vegetation may be computed by means of geometrical parameters.

The approximation of the (turbulent) Reynolds stresses is based on Boussinesqs principle of eddy viscosity, where the eddy viscosity may be computed with different closure models:

  • constant eddy viscosity predefined by the user
  • algebraic shear stress model (anisotropic / Elder)
  • k-e-turbulence model

Decoupled from the flow simulation the conservative transport of matter in solution or suspension may be computed by solving the depth-averaged advection diffusion equation.

Dr.-Ing. P.M. Schröder in January 2005

last change: 13/02/2005