TURBULENT RESISTANCE OF COMPLEX BED STRUCTURES

The influence of complex packing geometry on its frictional/hydrodynamic resistance was investigated both experimentally and theoretically. The complex bed structures were modelled using the cubic packing of spheres and different 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 approach these systems were regarded as compositions of two Representative Elementary Units (REU's) which contribute to the overall pressure drop within the apparatus. The values of the overall coefficient f₀ , characterising resistance 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.