In viscoelastic fluids, in stark contrast to viscous fluids, an outstanding open problem is the lack of rigorous foundation for, and agreement about, the governing model equations. The obstruction is that the microstructure of a viscoelastic fluid is arbitrarily diverse across biology and engineered materials, whereas the specifics of the microstructure determine the time and length scales of viscous and elastic behavior, and the microstructure response to forcing frequency, flow type and rate. A high premium is therefore placed on modeling, and especially on identification of classes of viscoelastic fluids for which the governing equations can be settled, so the focus can shift to the interplay between experiment, theory, and computation. Here the PIs propose a class of viscoelastic fluids, active, anisotropic fluids (AAFs), unifying three apparently diverse fluid systems (catalytic nanorod dispersions, swimming bacterial suspensions, and motor-driven actin filament gels) for which models, analysis, algorithms, and simulations have so far evolved independently. The PIs propose: to develop a rigorous modeling foundation that spans kinetic to continuum scales; to identify the common, leading-order mathematical structure at scale for all AAFs, and the lower-order structure that distinguishes among activation mechanisms and microstructural details; and, to illustrate the impact of these results for active nanorod dispersions and actin filament gels in both confined and free surface flows through new numerical algorithms and kinetic-to-continuum simulations.
|Effective start/end date||9/15/15 → 8/31/18|
- National Science Foundation (NSF)
free surface flow