Transonic buffet over airfoil - CFD DDES animation

The buffet instability is a well-known flow scenario in transonic airfoils that consists on self-sustained large amplitude shock oscillations that typically occur on the suction side but it can also take place on the pressure side. The unsteady motion of buffet occurs at frequencies of the same order of magnitude as the natural frequency of a typical aircraft structure that can lead to critical vibrations followed by fatigue failure. Therefore, it is crucial to understand the governing physics in order to be able to delay its onset or attenuate its harmful effects. Within the European Project H2020 TEAMAero (https://h2020-teamaero.eu/) we investigate the transonic buffet dynamics over the V2C laminar wing.

The present animations show a complete buffet cycle. The computation was undertaken using DDES simulations with the K-Epsilon (Chien’s damping) model near the wall. The purpose of this simulation is to collect flow snapshots to perform a POD decomposition and apply stochastic forcing techniques based on the reinjection of turbulent kinetic energy from high frequency and low energy POD modes (associated to chaotic turbulence) to model the energy transfer from the small eddies to the large ones. This general approach permits to reduce the excessive diffusion of turbulence models based on direct downscale cascade of turbulence and improve the prediction of the extent of the sheared regions in scenarios with highly detached flow.

We will keep you updated with the progress of the simulations! ;)

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