Flow past a porous spherical shell using matched asymptotic technique

Higher approximations are obtained for a uniform flow past a porous spherical shell than those obtained by Jones (1973). The matched asymptotic technique, developed by Proudman and Pearson (1957) has been used to find the solution of the flow field, which is divided into three regions - the innermost region, the porous region and the external region. The external (or free flow) region can be subdivided into the Stokes' region (near the shell) and the Oseen's region (away from the shell). The drag on the shell is discussed and several limiting cases of interest are deduced.