EFFECTS OF CO-ROTATING LONGITUDINAL VORTICES ON TURBULENT STRUCTURES IN THE LEG OF THE HORSESHOE VORTEX

Manipulation of the horseshoe vortex is a key technology for improvement of blade performance in the turbine blade passage, since the complicated interaction process of the vortices occurs around the blade. The target of the present study is to clarify the interaction process between the leg vortex of the horseshoe vortex produced by the blade and the longitudinal vortex produced by the vortex generator. The arrangement of the vortex generator wings which correspond to Common Flow Down configuration is discussed. The effect of the spacing of the longitudinal vortices is also tested. The narrow and wide spacing results in the different longitudinal vortex location at the top or side of the horseshoe vortex. The measurement by the hot wire anemometer which has an X-type rotating prong by a stepping motor provides three components of the velocity and the detailed turbulence kinetic energy and the Reynolds stress profiles giving the clear understanding of the complicated interaction process of the two vortices. The narrow spacing of the longitudinal vortex in Common Flow Down configuration shows the strong interaction of the horseshoe vortex and longitudinal vortex dynamics.