TEMPORAL ANALYSIS OF JET AND VORTEX ACTUATOR (JAVA) - INDUCED FLOWS
Hasan Güneş, Sertaç Çadırcı, Franceso Baldani, Bernd Peters, Ulrich Rist · 2008
A zero-net-mass flux Jet and Vortex Actuator (JaVA) device for active flow control was investigated in detail experimentally. The JaVA system in this study is derived from the work of Lachowicz et al., 1999. However, unlike there, we built a larger JaVA system and tested it in still water at much lower frequencies of order one. While attesting the same governing JaVA parameters (e.g, Reynolds number, scaled amplitude), such low-frequency values would allow us real-time observations with naked eye. The typical flow regimes induced by the JaVA system include angled jet, vertical jet, wall jet and vortex flows, as reported by Lachowicz et al., 1999. In this paper, we investigate the detailed quantitative temporal behaviour of basic JaVA-induced flow types utilizing the optical flow concept based on an image-gradient processing method. The temporal dynamics of instantaneous velocity fields obtained via optical flow are then investigated using Fourier analysis. 1