How to model trees?

 

On this page, a short advice for the numerical modeling of trees is given.

 

The easiest way of the numerical tree modeling is to assign a pressure loss coefficient λ [Pa (Pa m)-1] to vegetation containing grid cells.

 

Assume a permeable obstacle of streamwise depth d which fills the entire cross section of a duct (forced convection condition). The pressure loss coefficient λ gives the difference in static pressure Δpstat at the windward and leeward side, normalized by the dynamic pressure pdyn and the obsatclesís streamwise depth d, according to

 

 

       

 

with

 

    u        mean velocity component in streamwise direction

    d       obstacle's streamwise depth

    pluv    static pressure windward of the obstacle

    plee    static pressure leeward of the obstacle

    ρ        density of fluid

 

 

The pressure loss coefficient λ is a parameter depending on the internal structure of the obstacle and describes integrally the permeability.