The onset of turbulence in physiological pulsatile flow in a straight tube

 An empirical correlation for the onset of turbulence in physiological pulsatile flow is presented. We pumped three different test fluids of kinematic viscosity 0.008–0.035 cm²/s through four straight tubes 0.4–3.0 cm in diameter. A Scotch yoke mechanism provided an oscillatory sine wave flow component of known stroke volume and frequency. We adjusted the mean flow independently until we detected signal instabilities from hot film wall shear stress probes. The critical peak Reynolds number was found to correlate with the Womersley parameter and the Strouhal number as a power law function with a root-mean-square (rms) error of 15.2%. Experimental measurements of the laminar velocity profile are compared to theoretical predictions from Poiseuille’s law and Womersley’s solution. Received: 30 October 1995/Accepted: 7 April 1997