Post-Doc Theoretical And Numerical Analysis Of Liquid-Gas Turbulence

Context. Turbulence of heterogeneous fluids (non-miscible fluids separated by an interface) is encountered in several natural and industrial situations. Most of available theoretical descriptions of such flows generally focus on the dispersed regime, when one phase is much more abundant than the other and where fluid structures can readily be considered as spherical. When the two- phases are found in similar proportions (the dense regime), the shapes and dynamics of fluid structures are much more complex which make actual analytical descriptions inoperative. The DeltaPhi project funded by the ANR (National Research Agency) aims at exploiting a new framework developed by the coordinator (F. Thiesset, CNRS) which allows the morphodynamics of heterogeneous fluids turbulence to be characterized 1-3, webpage.

Figure 1. Numerical simulation of homogeneous isotropic turbulence of heterogeneous fluids. Full video available here

Position. A 18 months post-doctoral position is opened at the CORIA-CNRS laboratory (Normandy, France), in the Turbulence, Atomization, Spray and Chaos department. Mostly of theoretical nature, it aims at harnessing the newly proposed framework to probe the effects of different flow and physical parameters on the morphodynamical behavior of liquid structures in turbulence. For this purpose, Direct Numerical Simulations (DNSs) of homogeneous isotropic turbulence similar to those of Fig. 1 will be carried out using the ARCHER code. The DNS database will cover a wide range of flow parameters (turbulent Reynolds number, turbulent intensities) and fluid properties (viscosity, surface tension, density ratios, etc). These data will be post- processed using the dedicated Python library PyArcher and analyzed using the same methodology as 1-3. A second objective of the post-doctoral position is to derive scaling laws relating some relevant geometric and kinematic properties of the liquid-gas interface (surface area, curvature, stretch rate, etc) to some non-dimensional numbers such as the Reynolds and Weber numbers or the liquid volume fraction, etc.

Strong background in turbulence, two-phase flows, and their analysis is expected from candidates who wish to apply for this position. Some experience in numerical tools (git, supercomputing, object-oriented coding) flows would besides be valued.

Applicants should send a CV, a cover letter and any other relevant material to fabien.thiesset@coria.fr

1 THIESSET, F., DURET, Benjamin, MÉNARD, Thibaut, et al. Liquid transport in scale space. Journal of Fluid Mechanics, 2020, vol. 886. PDF

2 THIESSET, F., MÉNARD, T., et DUMOUCHEL, C. Space-scale-time dynamics of liquid–gas shear flow. Journal of Fluid Mechanics, 2021, vol. 912. PDF

3 GAUDING, M., THIESSET, F., VAREA, E., et al. Structure of iso-scalar sets. Journal of Fluid Mechanics, 2022, vol. 942. PDF

Physics: PhD or equivalent

ENGLISH: Excellent

Strong background in turbulence, two-phase flows, and their analysis is expected from candidates who wish to apply for this position. Some experience in numerical tools (git, supercomputing, object-oriented coding) flows would besides be valued.