A polymer molecule in solution is treated as a porous sphere with a spherically symmetric permeability distribution. Solvent motion in and around this sphere is described by the Debije- Brinkman equation (Navier-Stokes equation and Darcy equation combined). The model allows a straightforward calculation of the frictional properties of a polymer in shear flow (intrinsic viscosity) and in translation (friction coefficient). Calculations have been carried out for a radial dependence of the permeability of the form k(r)=K exp(Qr2). The calculations provide us with 0 detailed information about the solvent flow through and around the macromolecular coil.