Direct numerical simulation of flow in stenotic channel to understand the effect of stenotic morphology on turbulence

Abstract

A fundamental fluid dynamics study has been performed in order to understand the effect of shape of blockage in a stenotic channel on turbulence flow characteristics using direct numerical simulation (DNS) as a tool. DNS has been performed for four canonical types with identical degree of blockage (stenosis) but with varied morphological forms. The results revealed large-scale and small-scale features of the flow represented by the root mean square (rms) of velocity and vorticity statistics are type-dependent. The turbulent structures exhibited characteristic structures and mechanics very specific to the type of blockage. The analysis indicates that for given degree of stenosis, the turbulence characteristics are significantly dependent on the morphology of the blockage, and hence to quantify turbulence flow characteristics in stenosed channel, the stenosis shape is an important metric that needs to be considered. The results of this study are directly relevant to the flow dynamics in diseased stenotic coronary artery, in the context of the importance of stenotic morphology in addition to the height of the stenosis as an important indicator for the prediction of the flow dynamics in diseased coronary artery.

Keywords:

• roughness
• direct numerical simulation
• turbulent boundary layers

Acknowledgments

The author would like to acknowledge the medical imaging group Dr. Ozer and Dr. Shoenhagen M.D. for their valuable input to this study. The author would like to acknowledge Dr. Hygriv Rao, Cardiologist, CARE-GROUP, Hyderabad, India for his valuable input on this problem. The author would like to acknowlege support from NSF instrumentation grant to conduct the simulations.