Sequential Velocity Development in the Ascending and Descending Aorta of the Dog

A conical hot-film probe was used to measure instantaneous velocities in the ascending and descending aorta of anesthetized open-chest dogs. From these point measurements, the radial distributions of velocity were obtained over one cardiac cycle. In general, the hot-film measurements confirmed the observation that the velocity profiles tend to be flat with the highest rates of shear confined to the region of the wall. There were, however, significant variations in the detail from one dog to another. These variations in the shape of the profiles probably are a consequence of many geometrical factors, which include valve inlet geometry, configuration and orientation of the valve plane, and aortic curvature and branching in the descending aorta.