Abstract
The effects of vessel branching on hydrodynamic stability was investigated, using glass models of single branches, by comparing the critical Reynolds' numbers in branched tube systems with those obtained in a straight tube under identical conditions. The critical Reynolds' numbers obtained in the branched tubes ranged from 58 to 89% of those in the straight tube. No differences in hydrodynamic stability were detected with varying angles of branching.
It is pointed out that one cannot assume any particular value of the Reynolds' number for separation of flow into turbulent or laminar, particularly for oscillatory flow and flow past branches. Turbulence, or at least non-laminar flow, probably exists in all arteries greater than 1 or 2 mm in diameter. Branches would, therefore, appear to be sufficiently disturbing to blood flow to throw doubt on the validity of theoretical models assuming laminar flow.