Fig. 5. Characterization of fluid shear across the gap within a Taylor-Couette flow tank. (A) Using dead sperm as passively transported particles, results are provided for a single trial at a predicted shear of 0.5 s^–1 (see Eqn 1 and Eqn 2). Each data point is the speed of a single cell, plotted as a function of position along a cross-gap transect, beginning at the cross-over point of no translational velocity and running in a straight line towards the outer wall (perpendicular to the direction of fluid motion). The slope of the line is the fluid shear, and least-squares regression indicates an excellent fit of empirical and theoretical values (ANCOVA: F_1,12=0.45, P=0.50). (B) The entire data set for dead sperm trials (N=60), showing close agreement between predicted and experimental observations (ANCOVA: F_1,58=0.01,

P=0.92).