Length scales and interfacial area in two-phase turbulence

The interfacial area is a key factor influencing the exchange of mass, momentum, and energy between phases in two-phase flows, making it essential for understanding mixing, transport, and phase-change processes. In this work, we investigate the scaling behavior of the interfacial area in two-phase flows. We show that the interfacial area is only a function of Reynolds number and Weber number for a given void fraction in turbulence. To verify the scaling, we use high-fidelity numerical simulations of stationary two-phase turbulence. We first derive important length scales in the flow and present the resolution requirements for high-fidelity numerical simulations of these flows in various regimes. Then, using these resolved "DNS" simulation data, in grids upto 4096^3, we verify the validity and universality of the interfacial area scaling for a wide range of Taylor-scale Reynolds numbers and Weber numbers. The simulations are performed using the GPU-accelerated ExaFlow solver on Frontier and Aurora. Our results establish best practices for simulating two-phase turbulent flows and present a universal scaling law for the interfacial area, paving the way for improved modeling and prediction of mixing and transport in complex multiphase systems over wide-ranging flow conditions.