Dynamics of a droplet migration in oscillatory and pulsating microchannel flows and prediction and uncertainty quantification of its lateral equilibrium position using Multi Fidelity Gaussian processes

TL;DR

This study investigates droplet dynamics in oscillatory and pulsating microchannel flows, revealing new equilibrium positions and employing Multi Fidelity Gaussian processes for efficient prediction and uncertainty quantification of droplet behavior.

Contribution

It introduces a multi-fidelity Gaussian process approach to accurately predict droplet equilibrium positions in complex unsteady microchannel flows, reducing computational costs.

Findings

New equilibrium positions identified for droplets in oscillatory flows

Multi-fidelity models effectively predict fine-grid simulation results

Uncertainty quantification enhances confidence in simulation predictions

Abstract

Dynamics of a droplet in oscillatory and pulsating flows of a Newtonian fluid in a microchannel has been studied numerically. The effects of oscillation frequency, surface tension, and channel flow rate have been explored by simulating the drop within a microchannel. These types of flows introduce new equilibrium positions for the drop compared to steady flows with similar conditions. The simulation results are very sensitive to the grid resolution due to the unsteady behavior of the base flow. Therefore, a set of fine grids have been used in this study to capture the physics of this problem more accurately. However, these fine grids make the computations significantly expensive. Therefore, a Multi Fidelity Gaussian processes method with two levels of fidelity has been used to predict the results of the remaining fine-grid simulations along with their uncertainties based on their correlations with those of the coarse-grid cases over a wide range of input parameters.