19. The Application of Background Oriented Schlieren Method to Aircraft Wake Vortex Investigations

Vortex wakes of conventional aircraft and their propagating nature close to the ground have a great impact on the safety and efficiency of the traffic flow on an airport. The development of a measurement technique which helps detecting e.g. the density gradients in the air due to the wake vortices and understanding the nature of such a flow structure in its natural environment can improve the predictability of this hazardous phenomenon. Therefore, the practical aspects of the implementation of an advanced Schlieren technique on an airport are described in this chapter. Two experiments based on slightly different setups and locations relatively to the runway were conducted in order to assess the feasibility of the Background Oriented Schlieren method (BOS) for the detection and investigation of aircraft wake vortices. The evaluation of the obtained data indicated a sufficient ability of this technique to detect strong density gradient but on the other hand, turned out to be less efficient when dealing with the peculiarities of a large scale outdoor experiment.