Application of a porous media approach for vegetation flow resistance

This study investigates whether a porous media approach based on macroscopic flow parameters and a Forchheimer type equation can be applied for flow in emergent vegetation. Published data of permeability and flow resistance for two-dimensional arrays of stiff cylinders was analyzed. For the practical determination of flow resistance, a pore Reynolds number based on the mean void nearest neighbour distance between vegetation elements and the mean pore velocity is calculated. This allows the computation of a pore friction coefficient, which is used to calculate the source term in the momentum equation. The vegetation parameters needed for this approach can be derived either from geometry (for cylinder-like stems) or based on biomass and plant-specific parameters. The performance of the approach is shown for one test case. © 2012 Taylor & Francis Group, London