Many large arteries present a double curvature that is known to reduce the
development of flow stagnating regions, which are related to the formation of
arteriosclerosis. It is not known, however, how a helical geometry affects the
energetic properties of the flowing blood and whether these depend on the
presence of a rotation in the entry flow. This work analyzes the flow in a finite
length helical vessel of constant cross-sectional area in presence of a swirl at
the entrance. The analysis is performed by numerical simulations for one
geometric condition that is typical for large arteries. As expected, the optimal
entry flow rotation is found in correspondence of the natural helical twist of
the the vessel geometry. The energetic losses were minimized in a small range
between optimal rotation and no rotation. In any case, a helical vessel presents
a larger dissipation of kinetic energy than those found in a corresponding
straight vessel. Although limited to steady flow and one geometric configuration, this result provides a preliminary basis for considering whether the
rotation observed in the flow ejected from the heart ventricles could be part or
not of a physiological optimization.
