Experimental Studies on Non-Newtonian Fluid Flows as Analogues of Lava Flows: Toward a Numerical Model with a Cooling Crust

MIYAMOTO Hideaki, ITOH Kazumasa, KOGURE Junichi, TOSAKA Hiroyuki, TOKUNAGA Tomochika, FUKUI Katsunori, MOGI Katsuro

doi:10.11345/nctam.50.351

Through laboratory experiments and measurements, we confirmed that kaolin-water slurry and paraffin wax are very useful to simulate lava flows. Kaolin slurry is a good simulant for a slow moving isothermal lava flow which has a main rheological control. However, a theoretical analysis and some laboratory runs compared with real lava flows strongly suggest an intrinsic problem on this isothermal approach: the surface crust will be significant for a flow morphology after the transition time. To understand a development of a cooling crust and its complicated effect on a flow morphology, we have attempted laboratory experiments using paraffin wax which is especially useful for its relatively low solidus temperature. Although the movement of a flow with a surface crust is not fully understood, our simple analysis suggests that the maximum thickness attained by the inflation process before a breakout, can roughly be estimated by balancing the overpressure and tensile strength. Our model can also estimate the maximum lateral length between the original and the second flow unit after the breakout. These results will strongly help in understanding the complicated and unmodeled compound flow behaviour, which would greatly improve the accuracy of existing numerical models of lava flows.

Experimental Studies on Non-Newtonian Fluid Flows as Analogues of Lava Flows: Toward a Numerical Model with a Cooling Crust

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