MEMS sensors to resolve spatial variations in shear stress in a 3-D blood vessel bifurcation model

Coronary artery disease (CAD) preferentially develops at the arterial branching points or bifurcations. Hemodynamics, particularly wall shear stress, plays an important role in regulating the development of CAD. The advent of the microelectromechanical systems (MEMS) sensor provides a potential entry point to overcome the difficulty in measuring temporal and spatial variations in shear stress. We, hereby, demonstrate the application of a MEMS sensor to resolve circumferential variations in shear stress using a three-dimensional symmetric bifurcation model. Reynolds numbers ranging from 1.34 to 6.7 were chosen to simulate flow at the microcirculation level. At these low Reynolds numbers, the wall shear stress was highest at the divider of bifurcation, and relaxed to a lower value downstream from the bifurcation. Skin friction coefficient values (C_f), defined as local wall shear stress normalized by the upstream dynamic pressure, varied circumferentially by a factor of 2 or more from the medial wall at the divider to the lateral wall of bifurcation. These experimental skin friction coefficients at various positions were in close agreement with values derived from the Navier-Stokes solution.