Turbulent resistance of complex bed structures

The influence of complex packing geometry on its frictional/hydrodynamic re sistance was investigated both experimentally and theoretically. The comple x bed structures were modelled using the cubic packing of spheres and diffe rent number of thin bands inserted between the spheres. The turbulent flow resistance of the model systems was determined experimentally on the basis of pressure drop and air flow rate measurements. In the theoretical approac h these systems were regarded as compositions of two Representative Element ary Units (REU's) which contribute to the overall pressure drop within the apparatus. The values of the overall coefficient f(0) characterising resist ance of the complex geometry structures were correlated with the values of the local coefficients f(i) describing resistance of the particular REU's. The latter ones were independently estimated using the Computational Fluid Dynamics (CFD) code.