A Novel Method for Defining the Leeward Edge of the Planar Jet in Crossflow

To avoid the complexity of the edge definition by the half width, a new approach to defining the leeward edge of the planar jet in crossflow is introduced in this paper. Particle Image Velocimetry (PIV) experiments were performed to measure different flow regimes within the single jet and the dual jets configurations in crossflow. Based on the experimental data acquired, a series of velocity profiles were extracted from the flow field. In each profile, a velocity threshold was given to distinguish the regions sheltered and the regions not sheltered by the planar jet. The boundary of these regions was accordingly recognized as the leeward edge. Furthermore, fitting of the edge was carried out using a second order polynomial so as to enable a mathematical expression of the leeward edge. An application of the proposed approach towards the flow induced noise reduction using a planar jet is also discussed in this paper. In addition, the PIV frame assembly algorithm used in this study is reported.