HYDRAULIC APPROACH ON THE GAS CONVECTIONAL RESISTANCE OF THE CULM IN PHRAGMITES AUSTRALIS

Abstract

The gas convectional resistance of the culm in P. australis was analyzed with Darcy-Weisbach type equation. The head losses are occoured mainly at the node diaphragms and basal pith cavity. The friction losses at the inner walls excluded basal pith cavity are inversely proportional to the Reynolds number. The head losses coefficients at the node diaphragms are linearly proportional to a root of the kinetic heads. Therefore new head loss coefficients were defined. This research made clear the physical aspect why Darcy’s type equation is able to apply on the convection of the culm in P. australis. The mathematical model constructed in the present study was in good agreement with the experimental results.