Wake Vortex Investigation in WSG without / with End-effect

Abstract

An experimental study was carried out to establish a self-destructive wake vortex system. The study was made in the water towing tank in Göttingen (WSG), which was instrumented with a standard Stereoscopic PIV system and flow visualization setups. The tailoring of 4 vortices wake systems was achieved by employing a generic model with a main wing and several horizontal tail plains. By varying aspect ratios and incidences, various effects were generated and studied. The study exhibited that, with appropriate horizontal tail plain settings, the interaction of tail vortices with tip vortices may result in a promising self-destructive mechanism within the wake system in the sense that the vortex core experiences an instability and abrupt change of pattern. Typically, the interaction of wake vortex cores could be achieved as early as in 40 wing spans downstream with suitable tail settings. The possible influence from the finite movement in the water tank due to transient processes of the model (End-effect) was investigated. The end-effect could be essentially alleviated by isolating the working region with patented laboratory settings. The influence of the bottom and side wall effects was estimated from comparison of results from a larger water towing tank HSVA.