The high incidence of thromboembolic complications of mechanical heart valves (MHV) limits their success as permanent implants. The thrombogenicity of all MHV is primarily due to platelet activation by contact with foreign surfaces and by nonphysiological flow patterns. The latter include elevated flow stresses and regions of recirculation of blood that are induced by valve design characteristi...

This paper presents an approach to quantify the unsteady fluid forces, moments and mass transport generated by swimming animals, based on measurements of the surrounding flow field. These goals are accomplished within a framework that is independent of the vorticity field, making it unnecessary to directly resolve boundary layers on the animal, body–vortex interactions, or interactions among vo...

An experimental investigation was performed with two aims: (1) to clarify the existence of the dual leading-edge vortices (i.e. two vortices with the same sense of rotation located close to the leading edge above the leeward wing surface) observed on flapping wings in previous studies; (2) to study systematically the influences of kinematic and geometric parameters on such a vortical structure....

The objective of the study is a more detailed analysis of lung ventila tion under normal breathing conditions and for artificial, respirator-assisted ventilation. Therefore a realistic 3D model of the lung down to the 6 generation was generated to investigate the oscillatory flow through the branching network by DPIV. A transparent model made of silicone is used in combination with a refractive...

Time-synchronised flow velocity, temperature, and heat flux measurements were preformed to characterise the interaction of a single rising ellipsoidal bubble with the free convection flow from a heated vertical flat surface. The heat transfer measurements from the surface were provided by a hot film heat flux sensor calibrated using a pre-calibrated microfoil heat flux sensor. Two thermocouples...

This symposium approaches answers to these questions from multiple directions. Four primary sets of technological developments have come together in the past decade to make it possible to revisit each of these questions in innovative, quantitative ways. These developments are: a) highspeed digital video photography; b) algorithms for rapid analysis of digital images; c) laser based quantitative...

During ontogeny, animals undergo changes in size and shape that result in shifts in performance, behavior and resource use. These ontogenetic changes provide an opportunity to test hypotheses about how the growth of structures affects biological functions. In the present study, we ask how ontogenetic changes in skull biomechanics affect the ability of bluegill sunfish, a high-performance suctio...

Both body undulation and caudal fin flapping play essential locomotive roles while a fish is swimming, but how these two affect the swimming performance and hydrodynamics of fish individually is yet to be known. We implemented a biomimetic robotic fish that travel along a servo towing system, which can be regarded as “treadmill” of the model. Hydrodynamics was studied a...

This paper demonstrates a new performance enhancement methodology for Co-Flow Jet (CFJ) airfoils using discrete injection jets. This research is motivated by the hypothesis that a discrete CFJ (DCFJ) airfoil will generate both streamwise and spanwise vortex structures to achieve more effective turbulent mixing than an open slot CFJ airfoil. Aerodynamic forces and DPIV measurements show that the...