Vortex merging and splitting events in viscoelastic Taylor–Couette flow

Recent experiments have reported a novel transition to elasto-inertial turbulence in the Taylor–Couette flow of dilute polymer solution. Unlike previously transitions, this newly discovered scenario, dubbed vortex merging and splitting (VMS) transition, occurs centrifugally unstable regime mechanisms underlying it are two-dimensional: becomes chaotic due proliferation events where axisymmetric pairs may be either created (vortex splitting) or annihilated merging). In paper, we present direct numerical simulations, using finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive equation model dynamics, which reproduce experimental observations with great accuracy elucidate reasons for onset surprising dynamics. Starting from Newtonian limit increasing progressively fluid's elasticity, demonstrate that VMS dynamics is not associated well-known Taylor vortices, but steady pattern elastically induced known as diwhirls. The amount angular momentum carried by these elastic vortices increasingly small elasticity increases eventually reaches marginal level. When occurs, diwhirls become dynamically disconnected rest system move independently each other axial direction. It shown events, along local transient result interactions among diwhirls, complex spatio-temporal persists even at levels twice large those investigated experimentally.