Backflow Events and Flow Separation on Wings

Aviation plays a crucial role in connecting people and goods but it is also an important contributor to negative effects such as the global CO2 release as well as air pollution.

In the past, most studies focusing on development and optimisation of turbulence were mainly based on experimental research in wind tunnels, which proved both costly and at least partially unreliable. Simulations of turbulent flows, based on scale-resolving techniques such as large-eddy and direct numerical simulations (LES and DNS), allow an unprecedented insight into all details of the flow, albeit at a significant cost despite enormous advances in hardware and software.

The physics of flows undergoing separation and regions of extended flow reversal is poorly understood, and thus turbulence models are unreliable. In particular, the prediction of where, how often, and under what circumstances separation occurs is unclear.

The project aims at addressing these open questions by a new set of high-fidelity simulations at different angles of attack, to study the development of a separated flow region on airfoils. Using advanced visualisation techniques, we track individual separation bubbles, and link them to the characteristics of the turbulent boundary layer using in-situ data analysis as the simulation progresses.

The simulations will be the first ones to cover a wide range of angles of attack for a fully turbulent flow. The data, together with the analysis, provides a unique view at these separation processes, and may eventually be used to develop and validate advanced turbulence models, potentially based on reduced order and data-driven approaches.