(transferring large amount of liquid) phenomenon was observed only for the highly wetting
fluid at these critical junctions, which might be due to small irregularities in geometry and/or
container surfaces, showing even small contact irregularities can influence fluid behavior in a
significant way (Chen 2009).
CFE Interior Corner Flow (ICF) experiments studied capillary flows in interior corners of 2
tapered containers. The migration rates of 4 different flows (dry, wet, open loop, and bubbly)
in the units were observed and compared. Flow rates were in good agreement with predictions
for the dry tests, but faster than predicted for previously wetted surfaces and bubbly flow tests.
In many cases, the bubbles were separated during the bubble tests of ICF but small bubbles
were unhindered.
The CFE Contact Line (CL) study observed the contact line (where the liquid and solid surface
make contact) effect on fluid flow over a surface with and without pinning (a cut surface grove
to disrupt smooth fluid movement). Results showed pinning produced more rapid wave
motions and less fluid damping in a container than the smooth free surface. Larger contact
angles (angle between the liquid and the container surface) also produced the same trend as
pinning with respect to frequencies and damping rates. Fluid depth in the container was found
to have little effect on the fluid’s response to disturbances except in cases where shallow depth
tests were involved. In general, modeled and observed results were in best agreement for the
more predictable and confined movement with pinned contact line (Weislogel 2008).
CFE experiments were highly successful in uncovering microgravity fluid dynamics and the
complex interaction of geometry, contact angle, asymmetry, and gap wetting in static and
dynamic modes. Subsequent VG tests determined critical wetting conditions for perforated
sheets with perfectly wetting fluids. This combination is common in storage tanks and can serve
as models for screens and perforated sheets, plates, or vanes. Characterizing porous wicking
structures will help in designing passive systems to manage highly wetting fuels, cryogens,
thermal fluids, and contaminated aqueous solutions such as urine recyclers.
PUBLICATION(S)
Jenson RM, Weislogel MM, Klatte J, Dreyer ME. Dynamic fluid interface experiments aboard the
International Space Station: Model benchmarking dataset. Journal of Spacecraft and Rockets.
July-August, 2010; 47(4):670-679. doi: 10.2514/1.47343.
Chen Y, Weislogel MM, Jenson RM, Collicott SH, Dreyer M, Klatte J. The capillary flow
experiment aboard the International Space Station: Status. Acta Astronautica. 2009;65:861-
- doi: 10.1016/j.actaastro.2009.03.008.
Weislogel MM, Jenson RM, Tavan NT, Bunnell CT. Capillary flow experiments aboard ISS. 47th
Aerospace Sciences Meeting and Exhibit, Orlando, FL; 2009.