Shear stress in arterial stenoses: a momentum integral model.

A mathematical model is developed to investigate blood flow in arterial stenoses up to Reynolds numbers of 1000. The approach is based on Thwaites' method, normally used to treat laminar boundary layer development over a body in a freestream. The model is applicable to any axisymmetric stenosis geometry in all laminar physiological flow regimes, has a minimum of externally input parameters and is implemented as a short program on a personal computer. Maximum bounds on the expected errors are derived by comparison with known results from Poiseuille flow in a pipe. Agreement with shear stresses reported by other researchers using computational fluid dynamics is within 13% rms. The method has been specifically designed to be a useful predictive tool for biomedical investigators.