Fluidisation Air of a density of 0.716 kg/m³ and viscosity of 2.66-10^-5 Pa's is passing through spherical sand particle bed of a density of 2290 kg/m³ and an average X_sv, of 0.43 mm. At incipient fluidization, the bed height is 0.25 m and the apparent bed density is 820 kg/m . Determine the U_mf and pressure drop. Validate your calculation.