Unsteady Flow Phenomena in Models of Curved Arteries with Stents

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PROPOSAL NO.: CBET - 0729995PRINCIPAL INVESTIGATORS: Plesniak, Michael W.INSTITUTION: Polytechnic University of New YorkUnsteady Flow Phenomena in Models of Curved Arteries with StentsAn experimental study will examine the effects of perturbations to the Stokes layer on secondary flow structures in a curved pipe subjected to pulsatile flow. This work is motivated by issues associated with the insertion of stents to structurally reinforce arteries treated by angioplasty in patients with stenoses (blockages) resulting from the progressive, degenerative cardiovascular disease atherosclerosis. Heart disease is the number one killer of men and women in the US and developed countries world-wide. Medical procedures performed in the US to treat atherosclerosis cost tens of billions of dollars annually. A simplified model with the relevant features of a stent in a curved vessel will be constructed and probed with non-invasive optical velocimetry techniques including LDV and PIV. It is hypothesized that the orientation and position of the stent relative to the walls will affect the secondary flows in the curved vessels, which will impact cellular biochemical signaling that is responsible for vascular remodeling.The intellectual merit of the proposed study is to develop an understanding of the sensitivity/receptivity of viscous layers leading to pulsatile secondary flows in curved pipes (representative of curved arteries which are ubiquitous in the body). The forcing functions to be employed are based on physiologically relevant waveforms that are considerably more complex than simple sinusoidal forcing previously used in the relatively few studies of pulsatile flow in curved pipes. The rapid accelerations and decelerations of the flow, which are characteristics of blood pumped by the heart during systole and diastole, produce a richness of flow physics. In terms of broader applicability to fluid dynamics, such perturbations may be considered as passive flow control in curved pipes.The broader impacts of the proposed study include societal, educational, and technological components. The underlying societal motivation is combating heart disease. Not only is the price high in terms of mobidity and mortality, but the economic impact of necessary medical procedures is tremendous. Another societal broader impact of this program will be to promote participation of students from underrepresented groups. Because of its urban setting in Brooklyn, Polytechnic University has many programs in place to attract underrepresented groups. For example, Polytechnic''s PROMISE FUND has given disadvantaged high school students the opportunity to attend work with faculty on research projects during the summer. The PI is actively involved to engage Polytechnic University as a partner in the NSF-funded Central New York-Puerto Rico Alliance for Graduate Education and the Professoriate (AGEP) project intended to significantly increase the number of domestic students receiving doctoral degrees in the sciences, technology, engineering and mathematics (STEM), with special emphasis on underrepresented groups. Co-funded by the Biomedical Engineering, Particulate and Multiphase processes, and Thermal Transport Processes Programs.