Flow manipulation via body morphology and elasticity

Bhosale, Yashraj Rajendra

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https://hdl.handle.net/2142/122095 Copy

Description

Title

Flow manipulation via body morphology and elasticity

Author(s)

Bhosale, Yashraj Rajendra

Issue Date

2023-09-21

Director of Research (if dissertation) or Advisor (if thesis)

Gazzola, Mattia

Doctoral Committee Chair(s)

Gazzola, Mattia

Committee Member(s)

• Chamorro, Leonardo
• Hilgenfeldt, Sascha
• Juarez, Gabriel
• Goza, Andres

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• mechanics
• numerical algorithms
• flow–structure interaction
• streaming
• elasticity
• Cosserat rods

Abstract

Interaction between flow and soft structures involving multiple spatio-temporal scales, pervades biology and engineering spanning domains from bio-medical/physiological flows to microfluidics, where there exists an inextricable nexus between body morphology, compliant mechanics, flow environment interaction, control, and behavior. Of great interest are regimes characterized by equally important inertial, viscous, and elastic effects in which soft biological organisms, pliable microfluidic devices, and part-artificial part-living miniaturized robots reside. In these regimes, there exists a unique flow rectification effect, known as viscous streaming, whereby an immersed oscillating body can generate steady, robust, and precisely controllable flows that can be used to manipulate local surroundings. Despite its demonstrated potential in microfluidics, little is known about streaming when bodies with varying morphology (curvature and topology) or elasticity are involved. In this context, in this thesis we deploy simulations, theory and experiments to investigate the effects of body morphology (geometry) and elasticity on resulting streaming flows, to ultimately achieve novel flow manipulation capabilities. Towards this goal, my research activities have been organized into three main thrusts: (1) Streaming flow manipulation via body morphology variation. Viscous streaming refers to the rectified, steady flows that emerge when a liquid oscillates around an immersed microfeature, resulting in the generation of local, strong inertial effects that allow effective manipulation of flow and particles, within short time scales and compact footprints. Despite its potential, viscous streaming has been narrowly explored, with applications overwhelmingly employing classically understood bodies of uniform curvature (cylinders, spheres), thus limiting scope and application. Here, with the help of simulations and theory, we explore the use of multi-curvature geometries as a mechanism to modulate and rationally shape associated streaming flows. Building upon these insights, we experimentally show how multi-curvature designs, computationally obtained, give rise to rich flow repertoires, whose potential utility is then illustrated in compact, robust, and tunable devices for enhanced manipulation, filtering and separation of both synthetic and biological particles. (2) Body compliance--a new dimension for flow manipulation. Beside our recent developments in multi-curvature streaming, no effort has so far systematically considered the role of body elasticity. Yet, modulation by soft interfaces may be relevant in a multitude of settings, from pulsatile physiological flows or conformal microfluidics to elastic mini-robots in fluids, with relevance to both medicine and engineering. Further, soft biological organisms, such as bacteria or larvae, may also take advantage of streaming for feeding or locomotion. Motivated by these considerations, this thrust focuses on dissecting the effect of body elasticity on streaming flows and beyond. To be able to do so, i.e., accurately resolve the dynamics of soft structures immersed in viscous flows across scales, we developed a monolithic algorithm for solving incompressible flow–structure interaction (FSI) problems for mixed rigid/soft hyperelastic bodies based on remeshed-vortex methods. Through multiple benchmarks, we demonstrate the accuracy, robustness, and versatility of our monolithic solver. We next deploy our elastohydrodynamic solver, in conjunction with asymptotic theory analysis, to investigate streaming flows for soft bodies in two and three dimensions, by considering the minimal settings of a soft cylinder and sphere, respectively, immersed in an oscillatory flow. The resulting investigations reveal a novel, independent streaming process, tunable via body elasticity, and available even in Stokes flows unlike rigid body streaming. Thus, body compliance offers a new dimension and an expanded design space for microfluidic flow control. (3) Further expansion in flow manipulation via soft, slender, heterogeneous structures. This thrust aims at expanding the capabilities of our elastohydrodynamic solver beyond bulk solid mechanics and additionally capture the dynamics of immersed soft, slender, heterogeneous fibrous structures. Fiber-based organization of matter is pervasive in nature and engineering, from biological architectures made of cilia, hair, muscles or bones to polymers, composite materials, or soft robots. While simulations can support the analysis (and subsequent translational engineering) of these systems, extreme fibers' aspect-ratios, large elastic deformations, and two-way coupling with three-dimensional flows, all render the problem numerically challenging. To address this, we couple Cosserat rod theory, which exploits fibers' slenderness to capture their dynamics in one-dimensional, accurate fashion, with our vortex methods-based solver via the penalty immersed boundary technique. The favorable properties of the resultant hydroelastic solver are demonstrated against a battery of benchmarks, and further showcased in a range of multi-physics scenarios, involving magnetic actuation, viscous streaming, biomechanics, multi-body interaction, and self-propulsion.

Graduation Semester

2023-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Yashraj Bhosale

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