Effects of surface irregularities on flow resistance in differently shaped arterial stenoses

The combined influence of an asymmetric shape and surface irregularities has been explored in a computational study of flow through arterial stenoses with 48% areal occlusion. Contrary to the conclusion of an earlier investigation, namely that the resistance to laminar flow through a stenosed artery is being reduced in the presence of surface irregularities, the present predictions demonstrate that the flow resistance is practically unaffected by surface irregularities at low Reynolds numbers, whereas an excess pressure drop up to 10% above that for a smooth stenosis is observed for higher Reynolds numbers. For a given areal occlusion, the flow resistance is reduced with increasing degree of stenosis asymmetry and this effect may more than outweigh the influence of surface irregularities. This effect is moreover prevailing throughout the entire range of Reynolds numbers considered.