On the role of stretched polymer sheets in the dynamics of elasto-inertial turbulence*

Elasto inertial turbulence (EIT) is a chaotic state of flow that is driven by complex interactions between polymers, boundary conditions, and flow dynamics. EIT may occur over a range of Reynolds numbers, including subcritical and supercritical Reynolds numbers from the perspective of the inertial turbulence (flows without polymers). We investigate the transition from elastic dominated regime (EDR) to EIT in two-dimensional natural convection flows at low Rayleigh numbers. The flow are simulated using spectral methods and domain of short dimensions bounded by walls in the vertical direction and with periodic boundary condition in the horizontal direction. Isothermal boundary conditions at the walls impose a negative temperature gradient acting on the momentum equations via the Boussinesq approximation for buoyancy. The focus is on the dynamics of sheets formed by highly-stretched polymers and the mechanism that control the onset of EIT. Other numerical experiments are also considered to further isolate the physics at play and the influence of inertia, and the polymer parameters of the viscoelastic models. The presentation will discuss the similarities that exist in the dynamics of EIT in natural convection flows and channel flows, as well as possible connections with elastic turbulence.