Atsuko Namiki with her model volcano. Analog magmas (xanthan gum solutions, corn syrup solutions, containing bubbles and/or solid particles) are contained in a plastic shock tube. The shock tube is separated from the large vacuum chamber by two diaphagms. When the diaphragms rupture, the fluid is subjected to rapid decompression. We monitor the response of the fluid with a high speed camera (2000 frames/second) and pressure transducers.
Experimental appartus used to study wax tectonics (and model tectonic processes in the ice shells of Jupiter's icy moons). See Manga and Sinton (2004) for some results.
Our Thermo-Haake rheometer even has a microscope attached so that we can study rheological properties to the evolution of microstructure. Part of our interest in this topic is motivated by trying to understand the effects of implications of bubbles and crystals in magmas and lavas (see recent papers by Rust and Manga (2002) J. NonNewt. Fluid Mech., Rust and Manga (2002) J. Colloid Int. Sci., Saar et al. (2001) Earth Planet. Sci. Lett., Hoover et al. (2001) J. Volc. Geotherm. Res., Manga and Loewenberg (2001) J. Volc. Geotherm. Res.) We (actually Alison Rust with the help of Dave Senkovich) have also built our own couette rheometer to study the rheology of bubbles fluids. The diameter of the outer cylinder was 29 cm. Why so big? we are interested in the effects of bubble deformation. To get large deformations it helps to have large bubbles. Large bubbles requires a large gap. See the 2002 paper by Rust and Manga in the Journal of nonNewtonian Fluid Mechanics for more details.
Our new Anton Paar density meter (left) can measure the density of liquids to the nearest microgram/cubic centimeter. This is accurate enough to even determine the temperature-dependence of the coefficient of thermal expansion (i.e., second derviative of density as a function of temperature). The National Science Foundation provided the funded to buy the density meter and rheometer.
Small tank and Data acquisition system
Many of our convection experiments are performed in tank (above) containing 10-100 liters of fluid (see recent papers by Gonnerman et al. (2002) Geophys. Res. Lett., Jellinek et al. (2002) Geophys. Res. Lett., Manga et al. (2001) Phys. Fluids, Schaeffer and Manga (2001) Geophys. Res. Lett, Manga and Weeraratne (1999) Phys. Fluids). Of particular interest recently has been studies of thermochemical convection. We typically use a combination of thermocouples, heat flux probes, and time-lapse video to quantitatively characterize the flows. Labview is used to control the experiments and for data acquisition (right).
Left: Corn syrup is delivered in large tanker trucks. This always disturbs the police. Right: Syrup is pumped from the truck into the basement of McCone hall and into the tank and other storage containers.
Bruno Cagnoli (left) and Michael Manga (right) using a high speed digital video camera (2000 frames per second) in part of a study of the mechanics of pycroclastic flows.
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