Shock – Boundary Layer Interaction and Buffet on Wings at the Edge of the Flight Envelope

Description of the Problem

Shock buffet undermines both flight safety and wing structure. It occurs when super-sonic air pockets of air over a wing are terminated by normal shock waves and oscillate up and down the wing, resulting in flow disruption and loss of lift. It thereby leads to high dynamic loads on the wings, a highly unsteady wing wake, a rough flight, and increased structural fatigue of the wing. Thus, understanding and reliably predicting shock buffet is important for flight safety, efficiency, and new aircraft design concepts.

A two-part image. The main portion shows a large grey aircraft with blue-green vorticies of turbulent air coming off the trailing edge of the wings. A smaller inset shows air pressure around the vertical profile of the wing. This is a gradient from high pressure in red to low pressure in blue. Above the wing is a large pocket of low pressure, while the highest pressure is at the leading-bottom and trailing-bottom parts of the wing. Behind the trailing edge of the wing, several round circles of low pressure can be seen - these are portions of the vorticies seen in the larger image.

Scientific Relevance and Impact

At the level of basic research and flow physics, improving simulations of shock-buffet can help reveal the mechanisms that govern shock-boundary layer interactions in 3D flows, like those on wings and compressors. From a simulation science standpoint, this challenge offers the potential to establish reliable numerical tools and models, in particular those for near-wall behavior in large eddy simulations (LES), that can predict complex, non-equilibrium flows at realistically LARGE Reynolds numbers. These tools and models would then facilitate future exascale high-fidelity, full aircraft simulations.

Codes Used

FLEXI and Alya as reference comparison

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