Session C01: Awards Session: Presentation of Awards and DFD Fellowships (Otto LaPorte Lecture, Stanley Corrsin Award)

Otto LaPorte Lecture: Hydrodynamics of liquids at solid surfaces, from simple to complex fluids.

Hydrodynamics at the solid interface is a fundamental property of fluids, as important as their constitutive equation, in determining their flow. Historically, experimental evidence has been decisive in identifying the hydrodynamic boundary condition at the liquid-solid interface, and more particularly the so-called no-slip boundary condition that describes very successfully the flow of simple liquids on the macroscopic scale. But the growing interest in fluidic transport at small scales and in confined geometries, from friction and lubrication to ion transport in biological channels, membranes, or energy storage devices, has necessitated a more detailed understanding of the hydrodynamics of liquids on solids. Building on the pioneering experiments of Chan and Horn, I will show how the hydrodynamic force created by the drainage flow between two approaching surfaces, provides an unprecedented tool to probe the dynamics of liquids near surfaces. I will discuss the role of surface interactions and roughness, the role of liquid viscoelasticity and of solid compliance, for the formulation of an effective or intrinsic Navier boundary condition at the solid-liquid interface.   

Stanley Corrsin Award Lecture I: A multi-physics model of the human heart: an immersed-boundary implementation

Building a computational model of the human heart is a formidable task as it involves very complex geometries, the dynamics of deforming biological tissues, the transitional and turbulent hemodynamics, the myocardium electrophysiology, the strong multi-way interaction of all these systems and the heart connection with the main arteries and veins. Furthermore, in order for the model to be predictive, hundreds of million degrees of freedom are necessary and, even on supercomputers, they require simulation times of weeks or months, thus preventing the routine use of these models.

Immersed-boundary methods are very advantageous for this class of problems since they can cope with complex deforming domains while retaining the ease and efficiency of simple meshes. This allows also to exploit the latest GPU-acceleration technologies thus reproducing the full cardiac dynamics within a few hours.  

This innovative approach makes possible a systematic use of virtual models in cardiovascular research, thus reducing the extensive use of in–vivo experiments with their economical and ethical implications.    

Stanley Corrsin Award Lecture II: From Beating Hearts to Flapping Fins: Insights into Biological Flows Empowered by High-Fidelity Immersed Boundary Methods

The continuous growth in computing power coupled with new computational algorithms and data-enabled methods is opening up exciting areas for research and discovery at the intersection of fluid dynamics and biology. Consider the mammalian heart, which has been sculpted by millions of years of evolution into a flow pump par excellence. During the typical lifetime of a human, the heart will beat over three billion times and pump enough blood to fill sixty Olympic-sized swimming pools. Each of these billions of cardiac cycles is itself a manifestation of a complex and elegant interplay between several distinct physical domains including hemodynamics, electrophysiology, muscle mechanics, flow-induced valves dynamics, acoustics, and biochemistry. In the arena of biolocomotion, fish are known to employ their highly flexible bodies and fins to extract energy from vortices and propel themselves in water with grace and efficiency that is the envy of all engineers. The buzzing of mosquitoes might be annoying to us, but the lifecycle of these insects is intimately tied to the generation of aeroacoustic wing-tones in ways that we do not yet understand. Previous investigations of such problems were often limited by the tools at hand, but modern computational tools are enabling the exploration of such multi-physics problems with a level of fidelity and precision that is unprecedented. In my talk, I will describe how the power of high-fidelity sharp-interface immersed boundary methods has enabled us to attack problems ranging from the chemo-fluidics of clot formation in the heart and aeroacoustic sound generation by flying insects, to the hydrodynamic mechanisms that schooling fish may exploit to increase thrust and efficiency.