Dissolution finger growth in variable aperture fractures: Role of the tip-region flow field

We present high-resolution computations to demonstrate the influence of the tip-region flow field on dissolution finger morphology in variable aperture fractures. Linear fingers are observed for small values (<0.1) of the coefficient of variation of the aperture field, whereas for larger values, fingers exhibit significant branching and winding. A consequence of this behavior is that finger breakthrough times vary non-monotonically with the coefficient of variation of the aperture field. This non-monotonicity is a robust feature across almost all realizations for in-plane fracture dimensions > about 25 x 25 correlation lengths.