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Item A computational study on the stenosis circularity for a severe stenosed idealized artery(Pleiades journals, 2019) Prashantha, B.; Anish, S.Narrowing of blood vessels (stenosis) changes the nature of blood flow through the arteries. The altered flow structures at the downstream of stenosis may generate adverse effects on the arterial wall. Hence, an understanding of the effect of stenosis circularity on the flow behavior at the downstream of stenosis is clinically beneficial. The present study has been carried out on idealized stenosed artery model with severe case of stenosis (75% area reduction) but with the same cross-sectional area that has been selected for the study. The effect of different physiological states (pulse rates) study has been examined through using FLUENT Inc. solver by finite volume method, controlled through user-defined functions. The results indicate that the velocity profiles, oscillatory shear stress, and fluid residence time are significantly affected by the shape of the stenotic region. Fluid residence time in the downstream plays a significant role in understanding the hotspots for the secondary deposition/plaque. © Springer Nature Singapore Pte Ltd. 2019.Item Discrete-Phase Modelling of an Asymmetric Stenosis Artery Under Different Womersley Numbers(Springer Verlag, 2019) Prashantha, B.; Anish, S.Understanding the hemodynamics in the post-stenotic region of an asymmetric stenosis is of paramount importance in the study of atherosclerosis progression. Numerically, the analysis becomes more complex when a discrete phase is added to the continuous phase in order to understand the behaviour of atherogenic particles in a pulsatile flow environment. In the present study, discrete-phase modelling (DPM) of an asymmetric and symmetric stenosed artery models has been carried out at different Womersley numbers. The objective is to understand the correlation between the discrete-phase (atherogenic) particle behaviour with the characteristics of continuous phase (blood) under varying pulse frequencies. Continuous phase is modelled by time-averaged Navier–Stokes equations and solved by means of pressure implicit splitting of operators algorithm. DPM has been carried out with one-way coupling. The transport equations are solved in the Eulerian frame of reference, and the discrete phase is simulated in Lagrangian frame of reference. The study brings out the importance of helicity in the atherosclerosis progression. Result shows that the asymmetric stenosis model exhibits less helical flow structure and the vortical structures are not getting transported to the downstream. Consequently, the average particle residence time (PRT) of the atherogenic particles is one order higher than the symmetric stenosis model. Low PRT leads to enhanced mass transport in the arterial flow and triggers further occlusion/plaque build-up at the post-stenotic region. The extent of asymmetry in a diseased artery may be considered as a useful parameter in understanding the rate of progression of atherosclerosis. © 2018, King Fahd University of Petroleum & Minerals.