Interaction of wake vortices with rooftops

• Applicant: Professor Dr.-Ing. Eike Stumpf
• Subject Area: Fluid Mechanics
• Term: since 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387070961

Aircraft wake vortices consist of two counterrotating vortices after the roll-up process, which descend due to mutually induced velocities. Near airports, these vortices can hit buildings and cause considerable damage. Since this damage could not be explained by the prevailing theory that hold the circumferential velocities responsible for it, the macroscopic interaction behaviour between the vortex and the roof was investigated for different gable roof configurations in the first funding phase. It was shown that under certain conditions the vortices split up and travel across the roof surface like a tornado. Microscopic vortex structures, which form directly above the rooftop and influence the further vortex-roof interaction, are essential for this behavior. Within this project, the focus is put on these secondary vortex structures and their contribution to the overall interaction process. Numerically and with the help of new measurement techniques, it is now possible to analyze these microscopic structures with high spatial and temporal resolution. The findings are then to be transferred to other common roof shapes in order to categorize them and determine the level of risk. A hazard analysis for the buildings in the vicinity of Frankfurt Airport concludes the project.

• DFG Programme: Research Grants