Fabien Evrard, UIUC, USA

Title: 
Simulation of gas-liquid flows using piecewise-quadratic interface reconstructions

Fabien Evrard
Assistant Professor
Aerospace Engineering
University of Illinois Urbana-Champaign

Abstract: 
Gas-liquid flows involving complex interface deformation and breakup, such as those encountered in liquid atomization, are central to many technologies and natural processes, including fuel injection in propulsion systems, powder production through spray drying, and the generation of sea spray aerosols at the surface of the ocean. Despite their prevalence, gas-liquid flows remain notoriously difficult to simulate. Accurately predicting their dynamics requires numerical methods capable of resolving the intricate evolution of the interface between the immiscible phases, while also faithfully capturing the effects of surface tension. Among the wide variety of numerical frameworks developed for this purpose, approaches based on the geometric Volume-of-Fluid (VOF) method have proven highly effective. Their sharp representation of the gas-liquid interface and exact local conservation of phase volume make them particularly well suited to flows involving significant interface deformation and numerous topological changes. However, conventional geometric VOF methods also face important limitations associated with their piecewise-linear representation of the interface. This choice limits the order of accuracy of the interface transport and can lead to the artificial breakup of liquid structures, such as the spurious pinch-off of liquid ligaments or puncture of thin liquid sheets.

In this talk, we will present recent developments toward a VOF framework built upon piecewise-quadratic interface representations. We will show, through a collection of numerical test cases, that the proposed approach retains the geometric and conservative strengths of traditional VOF methods, while enabling higher accuracy and offering new capabilities for subgrid-scale interface capturing and modeling. These developments open the door to more computationally tractable and robustly mesh-convergent simulations of liquid atomization and other gas-liquid flows involving complex interface dynamics.

Bio: 
Fabien Evrard is an Assistant Professor of Aerospace Engineering at the University of Illinois Urbana-Champaign. He received a Diplôme d'Ingénieur in Aerospace Engineering from the ISAE-SupAéro and an M.Res. in Fundamental and Applied Mathematics from the University of Toulouse, followed by a Ph.D. in Mechanical Engineering from Imperial College London. He was awarded a Marie Skłodowska-Curie Actions Global Postdoctoral Fellowship and recently received the W. R. Marshall Award from the Institute for Liquid Atomization and Spray Systems. Fabien's research focuses on the modeling of strongly coupled multiphase flows using direct and large-eddy simulation, with applications ranging from plume-surface interactions during powered spacecraft landing to metal powder production via ultrasonic atomization for additive manufacturing.
----