Experimental Study on the Alleviation of Wake Vortices

An experimental study on the control of wake vortices was carried out in the water towing tank in Göttingen (WSG). A generic model with rectangular wing profiles was employed to generate a wake vortex system. The tailoring of a 4 vortices wake system was achieved by varying the horizontal tail plains with different aspect ratios and several incidences, generating various interactions in the wake system. Besides flow visualizations, quantitative measurements were made using a stereo (3C) PIV system. The study exhibited that the interaction of tail vortices with tip wing vortices may result in a promising self-destructive mechanism within the wake system in the sense that the vortex core experiences an instability and premature decay. Typically, the wake vortex cores could be destabilised after ~ 40 wing spans downstream with suitable tail settings, instead of more than 100 wing spans for that of a clean model. The possible influence from the finite movement in the water tank due to transient processes of the model (s.c. end-effects) was investigated. The influence of the bottom and side walls was estimated by the comparison with results from a larger water towing tank (HSVA)