title: Dimensionless analysis of valveless pumping in a thick-wall elastic tube: Application to the tubular embryonic heart.
abstract: The physical mechanism that drives blood flow in the valveless tubular embryonic heart is still debatable whether it is peristaltic flow or valveless dynamic suction. Previous studies of valveless pumping were concerned with either the role of the excitation parameters or the mechanisms that generate the unidirectional outflow. In this study, a dimensionless one-dimensional (1D) analysis of the valveless pumping due to local excitation at an asymmetric longitudinal location was performed for non-uniform thick-wall elastic tubes, including tubes with local bulging and tapering. A general tube law that accounts for wall thicknesses was implemented for describing the physically realistic dynamics of the tube and the two-step MacCormack algorithm was utilized for the numerical analysis. A comprehensive analysis was conducted to explore the affecting roles of the system (e.g., tube geometry) and the working (e.g., Strouhal number and flow friction parameter) parameters on the net outflow of the pump. The maximal positive net outflow in all the tested cases always occurred when the natural Strouhal number was about π. Flow reversals were observed only for relatively low friction parameters. A local bulging at the site of excitation and thick walls contributed to larger outflows, while tube tapering reduced the net outflow.
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kozlovsky
authors.affiliation: School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Rosenfeld
authors.affiliation: Ultrasound Unit in Obstetrics and Gynecology, Lis Maternity Hospital, Tel-Aviv Sourasky Medical Center, Tel-Aviv 64239, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel.
authors.forename: Ariel J
authors.initials: AJ
authors.lastname: Jaffa
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel. Electronic address: elad@post.tau.ac.il.
authors.forename: David
authors.initials: D
authors.lastname: Elad
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006321:Heart / Q000196:embryology / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008954:Models, Biological
keywords: Computational model; Impedance pump; Thick wall collapsible tubes; Tube law; Valveless pump