Influence of Dynamic Flap Movement on Maximum Lift and Wake Vortex Crow Instability

 

BIMOD provides a novel approach that combines modern system components to achieve two different effects with one mechanism of action: The increase of maximum lift to increase the eco-efficiency of aircraft configurations and the stimulation of vortex instabilities to minimize prescribed separation distances between aircraft.

 

Modern fly-by-wire aircraft with Advanced Dropped Hinged Flaps generally offer the architecture in which a periodical oscillation of the flaps is possible when an adapted actuator concept is applied. Either, this capability can be used for a periodic alteration of the spanwise lift distribution and with it the wake vortex centroid positions in order to accelerate exponential growth of natural vortex wake instabilities for fast vortex wake decay. Or, the constant periodic oscillation of flaps allows for higher deflection angles and respectively larger maximum lift coefficients compared to classical high-lift conditions with constant flap deflection angles due to the dynamic lift effect.

With the help of the approach pursued in the project, the flap geometry, and thus the structural weight, can be reduced and the separation distance between two aircraft reduced. The joint project BIMOD provides a detailed basis for the described approach. In addition to experimental investigations and aeroelastic analyses, a consistent preliminary aircraft design for a long-haul airliner using this technology is being carried out. This includes a comprehensive mission analysis with economic and ecological technology assessment and a recommendation to industry for further usability.

The joint project is carried out with the Institute of Aerospace Systems of RWTH Aachen University and the Chair of Aerodynamics and Fluid Mechanics at Technical University of Munich.