Session: 7.7.2 - Numerical Methods for Multiphase Flows II

Paper Number: 169912

169912 - Resolution Requirements for Numerical Simulations of Two-Phase Flows 

Abstract: 

In this presentation, we address the challenge of determining the adequate grid resolution required for properly resolving all the length and time scales (interfacial and turbulent features) in a two-phase flow simulation. Currently, a grid scaling criterion exists for direct numerical simulations (DNS) of single-phase flows, defined based on the Kolmogorov scale. However, a similar criterion does not exist for two-phase flows. 

This work leverages simulation data over a range of Weber and Reynolds numbers to propose a resolution requirement based on the Hinze scale of the flow. We keep track of the global interfacial area during the initial transient phase (where the dispersed phase undergoes rapid breakup and coalescence) and during the stationary state (where the breakup and coalescence balance each other). Additionally, we also calculate the PDF of the droplet size distributions during the stationary state. This proposed criterion demonstrated convergence of the interfacial and turbulent features for simulation cases with a Hinze scale above and below the Kolmogorov scale. This guarantees that numerical simulations will be well-resolved for all Weber and Reynolds numbers. 

This criterion will be a valuable tool for determining grid resolution and time-step requirements a-priori for DNS of two-phase flows and for estimating the corresponding computational cost. This work provides guidelines and best practices for numerical simulations of two-phase flows, which will accelerate physics discovery and model development.

Presenting Author: Pranav Nathan Georgia Institute of Technology

Presenting Author Biography: