Experimental study on high angle of attack of aerodynamic flow field phenomenon using flow visualization method and particle image velocimetry

Abstract

For flow over a delta wing a massive flow separation occurs at high angles of attack In such a case the aerodynamic characteristics are evidently dominated by the separated flows One of the most significant characteristics of the separated flows is the unsteady phenomenon which is accompanied with the development of large-scaled vortical flows Moreover the vortices generated at the leading edges may interfere with each other The present experiment was carried out in a recirculating-type water channel The characteristics of the vortex flow developed above a delta wing model were studied by means of flow visualization The angles of attack (?) of the delta wing model were in a range of 5°≦?≦ 30° respectively Particular attention was paid to the flow conditions under which the event of vortex breakdown took place The corresponding limiting-streamline patterns appeared on the surface of the delta wing model were of interest to study Further experiment was carried out with a NASA TP-1803 model and J31 model The dye injection method and the surface dot paint method were employed to unveil the vortex structure and the location of vortex breakdown associated with this model The PIV flow visualization technique was employed to observe local characteristics around the testing models Consequently discussion of the experimental findings with respect to the flow parameters of ? was carried out The impact due to the interaction between the vortices developed above this model is addressed in this report

Date of Award	2019
Original language	English
Supervisor	Jiun-Jih Miau (Supervisor)