Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Makina Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2016
Öğrenci: İBRAHİM CAN KÜÇÜKYILMAZ
Danışman: MEHMET METİN YAVUZ
Özet:In recent years, interest has increased in Unmanned Combat Air Vehicles (UCAVs) and Unmanned Air Vehicles (UAVs), which can be represented by simplified planforms including delta wings. Delta wings experience the formation of two counter-rotating vortices on the leeward side of the planform due to the shear layer separated from the windward side. At sufficiently high angle of attack, these vortices undergo sudden expansion, called vortex breakdown/burst, which is quite detrimental considering the aerodynamic performance of the wing. The present study investigates the Computational Fluid Dynamics (CFD) simulations of these vortical structures and the associated flow control with along-the-core blowing around 70° swept delta wing to primarily delay breakdown/burst location of these vortical structures. In the present study, different turbulence models with varied corrections are investigated using the commercially available software in order to predict the formation and breakdown of vortical structures accurately. Firstly, a mesh independency study is successfully achieved, and then detailed validation of the CFD models is carried out using previously conducted experimental studies. k-ω vi SST with curvature correction turbulence model is selected as the best numerical approach considering the accuracy of the results. In addition, along-the-core blowing control technique is applied to delay the vortex breakdown location. The effects of momentum coefficient and pitch angle on vortex breakdown location are investigated in detail. Pitch angles ranging from 7.5° to 60° are examined, and the results indicate that maximum vortex breakdown delay is achieved at pitch angles from 7.5° to 30°. Further increase in pitch angle decreases the effect of core blowing on flow structure and leads to less delay in vortex breakdown location. The results also indicate that as momentum coefficient increases, vortex breakdown delay increases almost linearly with the defined momentum coefficient interval ranging from 0.008 to 0.048.