Comparison of fully coupled fluid structure interaction and pseudo-steady state modelling of aortic valve hemodynamics.
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The mathematical modelling of the operation of heart valves is seen lately as a efficient method for prediction of some valvular diseases [1]. However, reliable mathematical model of heart valve operation needs to cover strong coupling between fluid flow and solid displacment and stresses, what results in very demanding and time consuming unsteady fluid-structure interaction (FSI) computations. The main aim of the paper is to assess application range and uncertanity of the pseudo-steady state approach for modelling hemodynamics of aortic valves comparing to the validated fully coupled fluid structure interaction model. Both the coupled FSI and pseudo-transient models of aortic valve leaflets were developed using Ansys Workbench platform. A 3D model cut-out of the aortic tract and symmetrically mirrored leaflet is treated as the domain under investigation. A comparison of successive valve leaflet expansion states was considered. The flow was modelled as a compressible fluid, taking into account the physical inclinations occurring in the actual section of the left ventricle and aorta. In order to mitigate the simplifications in geometry and the effects of compressible flow modelling, special treatment of the vertices between the leaflets was applied. Leaflets mechanobiology is simplified to only represent major stress and strain governing properties. The walls of the aortic segment, commissures and annulus are treated in a similar manner. The presented methodology is intended to become a tool for further research on the optimisation of the transcatheter aortic valve implantation (TAVI) procedure. The present study was carried out within the framework of a research project financed by the National Science Centre under grant agreement DEC-2024/54/E/ST8/00100.
