“…Annular flow between concentric cylinders (including purely tangential, purely longitudinal as well as helical deformation) is not new, and has been addressed in the literature for both classical [7,8,9,10,11] and fractional viscoelastic models considering the generalised Maxwell [12,13,14,15,16,17] and the generalised Oldroyd-B [18,19,20,21,22,23,24] models. Apart from the different fractional models considered, these works differ from each other in the boundary conditions used, and the method in which theoretical results are derived.…”