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ISSN Онлайн: 2642-0554

EFFECTS OF PERTURBATIONS INDUCED BY FRACTURED STENT ON SECONDARY FLOW STRUCTURES IN A CURVED ARTERY MODEL

Kartik V. Bulusu
Department of Mechanical and Aerospace Engineering The George Washington University 801 22nd Street, N.W, Washington, D.C. 20052

Christopher Popma
Department of Mechanical and Aerospace Engineering The George Washington University 801 22nd Street, N.W., Washington, D.C. 20052

Michael W. Plesniak
Maurice J. Zucrow Laboratories (formerly Thermal Sciences and Propulsion Center), School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA; Department of Mechanical and Aerospace Engineering The George Washington University

Аннотация

Arterial secondary flow structures are affected by pulsatility and multiple harmonics of physiological inflow conditions, resulting in multi-scale vortical patterns. Flow perturbations are produced by stent implants that are used as a treatment to atherosclerosis, a disease of the artery. These perturbations emanate from the Stokes' layer, due to changes in the inner wall surface roughness. The incidence of fractures in stent implants and concomitant flow perturbations result in secondary flow structures with complex, multi-scale morphologies and varying size-strength characteristics. These secondary flow structures are ultimately known to influence wall shear stress and exposure time of blood-borne particles that are closely related to atherogenesis, especially in arterial curvatures. In vitro experimental investigation of the complex secondary flow structures due to stent fractures is presented in this study. Particle image velocimetry (2C-2D PIV) techniques are used in conjunction with continuous wavelet transform (CWT) and λci-criterion for coherent structure detection. A comparison is made between unfractured and a certain "Type-IV" fracture stent models. The role of centrifugal forces towards the location, translation and breakdown in symmetry of secondary flow structures is explained using a "residual force" parameter.