Formation, maturation, and failure of viscosity-stabilized foams: application to volcanic eruptions

本项目将研究粘度稳定泡沫的稳定性和动力学。一个特别的焦点将是大的、分离的气泡形成的机制，然后通过岩浆泡沫上升，在表面爆炸。对表面张力为主的高含气率泡沫的实验表明，随着气泡尺寸的增大，这种解耦可能通过亚临界分叉发生。我们的目标是开发一个膜破裂的连续模型，解释这些气泡是如何生长的，然后将其纳入可变形颗粒悬浮流变学的离散数值模拟中。这将使我们能够确定超过屈服应力而导致岩浆爆炸的临界条件。

This project will investigate the stability and dynamics of viscosity-stabilized foams. A particular focus will be the mechanisms through which large, decoupled bubbles can form, and then ascend through a magma foam to burst explosively at the surface. Experiments on surface-tension dominated foams with high gas fraction suggest that this decoupling may occur through a sub-critical bifurcation as the bubble size increases. Our aim is to develop a continuum model of film rupture that explains how these bubbles grow, and then to incorporate this into discrete numerical simulations of the rheology of suspensions of deformable particles. This will allow us to identify the critical conditions at which the yield stress is exceeded to cause magmatic explosions.