Two phase flow in the dynamic Earth: Implications for melt flux and chemical differentiation

在地壳的下部，结晶固体和熔融岩石的混合物可能同时存在。该系统将发展流动不稳定性，以响应不同的强迫，特别是密度对比或构造强迫。可以设想三种基本情况：熔体被“挤出”、“通过”或“积聚”在晶体之间的间隙孔中，这些情况“占据”的参数空间将因作用力、力组合和熔体-岩石比的不同而不同。学生将专注于解决与理解从深到浅的粘性相通量有关的纯流体力学现象，这推动了地球内部快速的熔体运输和化学分化。学生的目标是在理论和不同的地质相关情况下建立不同强迫情景下熔体运输的特征和控制参数。为了达到这个目的，学生将应用不同作用力下两相流的第一性原理流体力学模型，并在无量纲参数空间中深入探索这些模型。特别是，学生将对重力和/或构造力驱动的非均质多孔介质中的微分流的影响进行全面研究。该理论的潜在推广包括通过地壳预测熔体通量对化学效应的影响。

In the lower parts of the Earth's crust, a mixture of crystalline solid and molten rock may exist simultaneously. This system will develop flow instabilities in response to different forcings, specifically to density contrasts or tectonic forcing. Three fundamental situations can be envisaged: melt is either "squeezed out", "fluxed through" or "accumulated in" interstitial pores between crystals, the parameter space that these situations "occupy" will differ with different forcings, force combinations and melt-rock ratios. The student will focus on addressing the pure fluid-mechanical phenomena relating to understanding the flux of the viscous phase from deep to shallow, which drives rapid melt transport and chemical differentiation within Earth. The student will aim to establish the characteristics and governing parameters of melt transport at different forcing scenarios both in theory and in different geologically relevant situations. To reach this aim, the student will apply first-principles fluid-mechanical modelling of two-phase flow under different forcings and explore these thoroughly over a dimensionless parameter space. In particular, the student will perform a comprehensive study of the effects of differential flow through a heterogeneous porous media driven by gravity and/or tectonic forcing. Potential generalizations of the theory include the implications of melt flux predictions through the Earths' crust for chemical effects.