uFluids@Home

μFluids@Home
Project
Status	Completed
Category	Engineering
Compute	CPU
Requires	None
Development
Developer	Steven H. Collicott
Author	Steven H. Collicott
Sponsor	Purdue University School of Aeronautics and Astronautics
Maintainer	μFluids@Home team (inactive)
Initial release	September 19, 2005  (21 years ago)
Discontinued	July 22, 2012  (14 years ago)
Software
Operating system	Cross-platform (Windows, Linux, macOS)
Size	~500 kB per work unit
BOINC statistics
Stats as of	June 29, 2011  (15 years ago)
Active hosts	2,340
Metadata
Website	http://www.ufluids.net/
License	Unknown

μFluids@Home (also written uFluids@Home) was a volunteer computing project built on the BOINC platform, operated by Purdue University's School of Aeronautics and Astronautics. The project used the Surface Evolver program, a finite-element package for modeling surfaces shaped by surface tension, to simulate two-phase flow behavior in microgravity and microfluidics problems.

The Neil Armstrong Hall of Engineering at Purdue University, home to the School of Aeronautics and Astronautics.

Overview

According to the project's own description, μFluids was "a massively distributed computer simulation of two-phase fluid behavior in microgravity and microfluidics problems." Its stated goal was to design better satellite propellant management devices and to address two-phase flow in microchannel and MEMS devices. Volunteers contributed idle CPU time on their home computers to run the Surface Evolver simulations that underpinned this research.

The project's purpose, as summarized by Wikipedia, was to develop better methods for managing liquid rocket propellants in microgravity, and to investigate two-phase flow in MEMS devices, taking into account factors such as surface tension. Systems using electrowetting, channel geometry, and hydrophobic or hydrophilic coatings to allow the smooth passage of fluids could then be designed, with potential applications in compact medical devices, biosensors, and fuel cells.

History

μFluids@Home was developed at Purdue University under Professor Steven H. Collicott of the School of Aeronautics and Astronautics. Collicott's research group specializes in the use of the Surface Evolver code for capillary fluid statics problems, work that traces back to support for the Gravity Probe-B satellite beginning in 1993.

Wikidata records the project's inception as 19 September 2005. Community discussion of the project on BOINC-oriented forums is documented from at least 2007, when the project was still described as being in a testing phase with no XML statistics feed yet available. Volunteers continued to join BOINC teams for μFluids into 2011.

The project's official domain, ufluids.net, was still being referenced in project listings as late as 2012. No BOINC work distribution has been documented since. As of 2026 the domain still resolves and serves a static description page, but its backing database is offline, returning a MySQL connection error rather than live project statistics. No archived RAC, host count, or user count statistics for μFluids appear to have survived on third-party BOINC statistics aggregators, and the project's precise shutdown date does not appear to have been formally documented.

Research goals

Purdue's aerospace engineering program, through Professor Collicott's group, has long focused on capillary effects in weightless environments, including designing propellant gauging and management systems for satellites. Related Purdue research covered by the university's news service examined fuel injection behavior in rocket engines, and lower-cost approaches to lab-on-a-chip device fabrication.

These themes, propellant management, MEMS two-phase flow, and low-cost microfluidic devices, map directly onto the stated goals of the μFluids@Home project.

A central physical relationship in this class of problem is the Young-Laplace equation, which relates the pressure difference across a curved liquid interface to its surface tension and curvature:

$\mathrm{\Delta }p=\gamma (\frac{1}{R_1}+\frac{1}{R_2})$

where $\mathrm{\Delta }p$ is the pressure difference across the interface, $\gamma$ is the surface tension, and $R_1$ and $R_2$ are the principal radii of curvature of the surface. In microgravity, where body forces on a fluid are negligible, this capillary pressure term dominates fluid shape and behavior, which is precisely the regime the Surface Evolver software is designed to model.

A NASA KC-135 reduced-gravity aircraft. Parabolic flights of this kind have historically been used by Purdue aerospace researchers to test low-gravity fluid behavior experimentally.

Software and technology

μFluids@Home distributed Surface Evolver simulation runs to volunteers' computers via the standard BOINC client. Surface Evolver itself is an interactive finite-element program, originally written by Kenneth Brakke at The Geometry Center with support from the National Science Foundation, that represents a surface as a union of triangular facets and evolves it toward minimal energy by a gradient descent method.

Per the project's own application notes, μFluids had no BOINC screensaver component. Individual work unit CPU times were generally less than 20 hours, and work units averaged around 500 kB in size. Because of the relatively small and infrequent nature of the work units compared to higher-profile projects, volunteers were advised that many work units would be needed to accumulate credit comparable to projects such as SETI@home or climateprediction.net.

Community

μFluids attracted small dedicated crunching teams on general-purpose BOINC community sites. The Australian technology community Whirlpool maintained a team page and statistics link for μFluids@Home participants, and the project was tracked on the SETI.USA forums, where new volunteers reported joining μFluids alongside other contemporary BOINC projects into 2011.

Publications

The following papers, authored by researchers associated with Professor Collicott's group at Purdue, cover the capillary fluids and two-phase flow problems that μFluids@Home was built to help investigate:

1. Manning, Robert and Steven Collicott. "Liquid Plugs in Rectangular Channels Under a Transverse Gravity Field". 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition (2010). DOI 10.2514/6.2010-1476.
2. Braun, Jonathan and Steven Collicott. "Zero-Gravity Stability of Droplets in a Bent Circular Cylinder". 44th AIAA Aerospace Sciences Meeting and Exhibit (2006). DOI 10.2514/6.2006-732.
3. Manning, Robert and Steven Collicott. "Bubble Penetration Through a Single Layer Sphere Bed". 44th AIAA Aerospace Sciences Meeting and Exhibit (2006). DOI 10.2514/6.2006-736.

Surface tension shapes a liquid interface, the same physics that Surface Evolver models numerically and that μFluids@Home computed at scale.

See also

• BOINC
• SETI@home
• Surface Evolver
• Purdue University