Speaker
Description
Coupled free-flow and porous-media flow phenomena are ubiquitous in nature. While research on single-phase coupling has reached a mature stage, studies on two-phase coupling remain insufficient, and the underlying coupling mechanisms are not yet well clarified. To elucidate the coupling mechanism between two-phase porous-media flow and free flow, this paper starts from the microscopic pore scale and derives interface conditions for two-phase Darcy–free-flow coupling in the transition region using a nonlocal volume-averaging approach. The results indicate that, at the coupling interface, the normal velocity and the normal stress are continuous, whereas the tangential stress exhibits a jump, which can also be manifested as tangential velocity slip. Subsequently, pore-scale numerical simulations are conducted to investigate the distributions of velocity and pressure within the transition region and to provide a preliminary validation of the proposed interface conditions. Finally, macroscopic-scale numerical simulations are performed based on the derived interface conditions: the free-flow region is described by the Navier–Stokes equations, and the porous-medium region is modeled using the classical two-phase Darcy formulation. Interface tracking is achieved via the volume-of-fluid method coupled with piecewise linear interface construction. Comparisons with available experimental data and pore-scale Navier–Stokes solutions confirm the validity of the proposed macroscopic numerical approach.
| Country | China |
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