Complex fluids flow and transport governs the production of European and global industries, along with natural hazards.
These processes are extremely challenging to control, because theories for such flows have large gaps, especially for yield-stress fluids (that flow when sheared strongly, but are solids otherwise).
Recent experiments and simulations underline that yield-stress fluids should be modelled as elasto-visco-plastic (EVP). The project proposes simulations of turbulent bubbly flows of EVP fluids as part of the ERC project StG-2019-MUCUS (852529), aiming to revolutionize understanding of yield-stress fluid flow over surfaces. Inertial bubbly flows of yield-stress fluids have not been studied experimentally or computationally.
Surfactants are often present or added to manipulate the flow and bubble distribution.
The project will perform direct numerical simulations (DNS) of turbulent bubbly channel flows to examine roles of EVP rheology and surfactant by fully parallelized 3D methods: finite-difference methods with front-tracking (with surfactant) and volume-of-fluid (no surfactant).
The incompressible Navier-Stokes equations are solved using an efficient FFT-based pressure projection method allowing massively parallel simulations of turbulent flows, fully coupled with the evolution equations of EVP stresses and surfactant concentrations.
Pioneering results will be achieved by methods that recently enabled DNS of EVP turbulence, and viscoelastic bubbly turbulence with surfactants.