Robert Hunt

Publications

  1. 10. FIEVel: A Fast, InExpensive Velocimeter based on an optical mouse sensor

    R. Hunt, E. Silver, D.M. Harris

    arXiv, Oct. 2024

    DOI: 10.48550/arXiv.2410.23176
    FIEVel

    FIEVel uses a common optical mouse sensor to measure fluid velocities at a sample rate over 6kHz for orders of magnitude lower in cost than devices used for comparable measurements. After proposing the work and making a prototype, I led writing a proposal with Dan Harris and Eli Silver for a Hazeltine Innovation Award which was funded for $50,000. We show FIEVel is capable of resolving turbulence spectra in a grid-generated turbulent flow, with exciting potential applications in research, education, and industry. Eli is leading the development of an open-source project which includes the sensor and related software and hardware, found here.

  2. 9. Diffusion-limited settling of highly porous particles in density-stratified fluids

    R. Hunt, R. Camassa, R.M. McLaughlin, D.M. Harris

    arXiv, Sep. 2024

    DOI: 10.48550/arXiv.2409.02419
    Diffusion-limited settling of highly porous particles in density-stratified fluids

    This study investigates the settling behavior of porous particles in stratified fluids, motivated by carbon sequestration in the ocean. In the low Rayleigh number regime, the motion of these particles is determined by the rate at which they absorb salt, causing small particles to settle faster and for the settling of large aspect ratio particles to be determined by the thin dimension. This has been my pet/side project for a while, and I am very glad it is now public! Check out this video I made for more info.

  3. 8. OpenFlume: An accessible and reproducible benchtop flume for research and education

    M. Lewis, E. Silver, R. Hunt, D.M. Harris

    HardwareX, Sep. 2024

    DOI: 10.1016/j.ohx.2024.e00583
    OpenFlume: An accessible and reproducible benchtop flume for research and education

    OpenFlume is an open-source recirculating flume for research and education in fluid dynamics. Led by master's student Maya Lewis and research engineer Eli Silver, this work describes the design and construction of the flume, which is built for around $1000 in parts using accesible tools and materials. I worked with Eli when he was an undergraduate to design a prototype of the flume as part of publication [6] below. I also worked with Maya during her master's to analytically model the flow in the flume and use various experimental techniques to validate the model and characterize the flow behavior.

  4. 7. Interactions and pattern formation in a macroscopic magnetocapillary SALR system of mermaid cereal

    A. Hooshanginejad, J.-W. Barotta, V. Spradlin, G. Pucci, R. Hunt, D.M. Harris

    Nature Communications, June 2024

    DOI: 10.1038/s41467-024-49754-4
    Interactions and pattern formation in a macroscopic magnetocapillary SALR system of mermaid cereal

    This work, led by Navid Hooshanginejad, explores pattern formation and concentration-dependent behavior in a system with combined effects of magnetic and capillary forces. I found and analyzed exact solutions for critical transitions between regimes in this system (detailed in Supplementary Material), and I also contributed a surface visualization of the capillary effects (pictured above) which was included in a winning video submitted to the 2023 American Physical Society Gallery of Soft Matter.

  5. 6. Drag on a partially immersed sphere at the capillary scale

    R. Hunt, Z. Zhao, E. Silver, J. Yan, Y. Bazilevs, D.M. Harris

    Physical Review Fluids (Editor's Suggestion), July 2023

    DOI: 10.1103/PhysRevFluids.8.084003
    Drag on a partially immersed sphere at the capillary scale

    This study examines the drag forces on a partially immersed sphere at an air-water interface. Here, the drag can be dominated by gravity effects, causing drag forces much greater than in the fully immersed case. This free-surface drag is not caused by outgoing waves, but instead by asymmetric pressure loading related to inertial effects and flow separation. At small scales, surface tension also plays an important role; superhydrophobic coatings, typically used for drag reduction, can actually increase the drag in this regime. I led modeling and experimental efforts for this work and worked with undergraduate/research engineer Eli Silver to design the recirculating flume, leading to the development and release of OpenFlume.

  6. 5. SurferBot: a wave-propelled aquatic vibrobot

    E. Rhee, R. Hunt, S.J. Thomson, D.M. Harris

    Bioinspiration & Biomimetics, July 2022

    DOI: 10.1088/1748-3190/ac7863
    SurferBot: a wave-propelled aquatic vibrobot

    Led by undergraduate Eugene Rhee, this work introduces SurferBot, a vibrating surface robot that propels itself by generating an asymmetric wavefield. I worked with Eugene to design SurferBot and measure its forcing, generated wavefield, and subsequent motion. We also made a video and designed an outreach activity which has been run at several GirlsGetMath@ICERM events, local libraries, and other organizations.

  7. 4. Part I: Diffusion-Induced Flows and Particulate Aggregation, Part II: Experiments and Modeling of Replacement Aortic Valves, Part III: Enhanced Diffusion in Wall-Driven Shear Flows

    R. Hunt

    Ph.D. Thesis, The University of North Carolina at Chapel Hill, Aug. 2021

    DOI: 10.17615/zrsp-q361
    Ph.D. Thesis: Diffusion-Induced Flows, Replacement Aortic Valves, and Enhanced Diffusion in Wall-Driven Shear Flows

    This thesis compiles my contributions to my first 3 publications below, as well as related work.

  8. 3. Enhanced diffusivity and skewness of a diffusing tracer in the presence of an oscillating wall

    L. Ding, R. Hunt, R.M. McLaughlin, H. Woodie

    Research in the Mathematical Sciences, Jan. 2021

    DOI: 10.1007/s40687-021-00267-2
    Enhanced diffusivity and skewness of a diffusing tracer in the presence of an oscillating wall

    This work investigates the effective diffusivity of tracers near oscillating walls, characterizing a diffusion-driven pumping mechanism for localized sources near oscillating walls. I worked with undergrad Hunter Woodie to develop the experimental setup and analyze the data. Lingyun Ding led the asymptotic analysis.

  9. 2. Bioprosthetic Aortic Valve Diameter and Thickness Are Directly Related to Leaflet Fluttering: Results from a Combined Experimental and Computational Modeling Study

    J.H. Lee, L.N. Scotten, R. Hunt, T.G. Caranasos, J.P. Vavalle, B.E. Griffith

    JTCVS Open, Sept. 2020

    DOI: 10.1016/j.xjon.2020.09.002
    Bioprosthetic Aortic Valve Diameter and Thickness Are Directly Related to Leaflet Fluttering

    This study examines the relationship between valve dimensions and leaflet fluttering in bioprosthetic aortic valves. I contributed some experiments as well as introduced a model for the leaflet fluttering frequency as a function of flow rate and valve geometry. More of my experiments and analysis related to this problem which aren't included here can be found in my thesis.

  10. 1. A first-principle mechanism for particulate aggregation and self-assembly in stratified fluids

    R. Camassa, D.M. Harris, R. Hunt, Z. Kilic, R.M. McLaughlin

    Nature Communications, Dec. 2019

    DOI: 10.1038/s41467-019-13643-y
    A first-principle mechanism for particulate aggregation and self-assembly in stratified fluids

    This paper presents a fundamental mechanism for particle aggregation in stratified fluids where a solute gradient interacting with a particle induces a fluid flow. This flow creates a force between particles which can cause them to aggregate and remain bound together in the absence of adhesion. I used analytical and numerical methods including singularity techniques and Stokesian dynamics simulations to model the particle interactions. I also developed experiments to validate the induced flow and particle dynamics, and I made this video to help explain the work.