Flow Structure and Transition to Local Turbulence Downstream of an Asymmetric Narrowing that Imitates Arterial Stenosis

Abstract

The results of experimental studies and numerical simulation of the flow structure in the separation region downstream of an asymmetric narrowing of smooth canal that simulates 70% one-sided stenosis of the artery are presented. The Reynolds number was equal to 1800. The instantaneous flow velocity vector fields were measured using the SIV technique. The numerical solution was obtained by the large eddy simulation (LES) method. Setting the disturbances in numerical simulation close to the experimental conditions made it possible to obtain a satisfactory agreement between the calculated and experimental velocity fields and the components of the Reynolds stress tensor. The data on formation of the local flow turbulence region behind the constriction and subsequent downstream flow relaminarization are obtained. It is shown that a pair of secondary eddies localized within the region of flow separation is formed near the throat of the constriction.