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AuthorOlcay, A. B.
AuthorAmindari, A.
AuthorKirkkopru, K.
AuthorYalcin, H. C.
Available date2018-03-20T06:08:44Z
Publication Date2018-03-01
Publication NameJournal of Applied Fluid Mechanics JAFM
Identifierhttp://dx.doi.org/10.29252/jafm.11.02.28185
ISSN17353572
URIwww.jafmonline.net
URIhttps://goo.gl/S7xr2a
URIhttp://hdl.handle.net/10576/6439
AbstractIsfahan University of Technology. The aortic valve is located at left ventricular outlet and is exposed to the highest pressure in the cardiovascular system. Problems associated with the valve leaflet movement can cause complications for the heart. Specifically, aortic stenosis (AS) arises when aortic leaflets do not efficiently open. In the present study, Lagrangian Coherent Structures (LCSs) were utilized by processing a variety of Computational Fluid Dynamics (CFD) models velocity vector data further to identify the characteristics of AS jets. Particularly, effective orifice areas (EOA) for different cases were accurately identified from unstable manifolds of finite time Lyapunov exponent (FTLE) fields. Calcified leaflets were modeled by setting the leaflet's Young modulus to 10 MPa and 20 MPa for moderately and severely calcified leaflets respectively while a healthy leaflet's Young modulus was assigned to be 2 MPa. Increase in calcification degree of the leaflet caused destruction of the vortex structures near the fibrosa layer of the leaflet indicating a malfunctioning for the movement mechanism of the leaflet. Furthermore, when we analyzed stable manifolds, we identified a blockage region at the flow upstream due to the stagnant blood here. Compared to a healthy case, for the calcified valve, this blockage region was enlarged, implying an increase in AS jet velocity and wall shear stress on leaflets. As a conclusion, results from the present study indicate that aortic leaflet malfunctioning could be accurately evaluated when LCS technique was employed by post processing velocity vector data from CFD. Such precise analysis is not possible using the Eulerian CFD approach or a Doppler echocardiography since these methods are based on only analyzing instantaneous flow quantities and they overlook fluid flow characteristics of highly unsteady flows.
Languageen
PublisherJAFM
SubjectAortic valve
Calcification
Computational fluid dynamics
Fluid structure interaction
Hemodynamics
Lagrangian coherent structures
Pressure
Stenosis
Vortex
Wall shear stress
TitleCharacterization of disturbed hemodynamics due to stenosed aortic jets with a Lagrangian Coherent structures technique
TypeArticle
Pagination375-384
Issue Number2
Volume Number11
ESSN1735-3645
dc.accessType Open Access


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