Experimental and Model Study of a Swirling Fluid Flow in a Converging Channel As a Simulation of Blood Flow in the Heart and Aorta

Study of swirling flows in channels corresponding to the static approximation of flow channels of the heart and major vessels with a longitudinal–radial profile zR² = const and a concave streamlined surface at the beginning of the longitudinal coordinate has been carried out. A comparative analysis of the flow structure in channel configurations zR^N = const, where N = –1, 1, 2, 3, in the absence and presence of a concave surface was carried out. The numerical modeling was compared with the results of hydrodynamic experiments on the flow characteristics and the shape of the flow lines. The numerical model was used to determine the velocity structure, viscous friction losses, and shear stresses. Numerical modeling of steady-state flows for channels without a concave surface showed that in the channel zR² = const there is a stable vortex flow structure with the lowest viscous friction losses. The presence of a concave surface of sufficient size significantly reduces viscous friction losses and shear stresses in both the steady state and pulsed modes.