Idea menarik untuk meningkatkan ciri-ciri aerodinamik melalui perangkapan vorteks yang stabil kekal sebagai konsep baru. Dalam usaha untuk meneroka konsep lif tinggi ini, suatu penyiasatan visualisasi aliran kualitatif telah dijalankan atas satu disk berputaran 7.5 rpm dengan protrusi permukaan atas. Visualisasi aliran telah digunakan dalam medan aliran dengan penyuntikan pewarna menggunakan picagari yang dihubungkan dengan jarum suntik. dan perkembangan aliran tersebut direkodkan dalam bentuk video. Imej pegun diekstrak daripada video tersebut dan diproses dengan Photoshop untuk menjadi urutan imej bagi menggambarkan gerakan atas kertas. Dua protrusi mempunyai bentuk segi tiga sudut kanan telah diuji – satu lurus dan diselaraskan dengan radius disk, dan satu protrusi pada sudut 30 darjah dari radius disk. Ia diperhatikan bahawa suatu vorteks jelas dibentuk belakang protrusi tersebut dan vorteks ini berkecenderungan untuk berkembang dalam dalam arah panjang protrusi. Bagaimana pun, ia diperhatikan bahawa perkembangan vorteks ini kurang jelas apabila protrusi bersudut diuji. Ia didapati bahawa suatu disk rata tanpa protrusi tidak menghasilkan satu vorteks koheren langsung. Kajian ini telah mencapai objektif untuk memvisualisasikan medan aliran dan memberi cadangan, seperti menaiktarafkan setup eksperimen dan ujian pelbagai protrusi, untuk melaksanakan kerja masa depan bagi melanjutkan penyelidikan and perkembangan dalam bidang ini.
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The attractive idea of augmenting aerodynamic characteristics through the trapping of a stable vortex still remains a novel concept. In an effort to explore this high lift concept, a qualitative flow visualization investigation on a rotating disk with the addition of an upper surface protrusion has been conducted. Flow visualization was applied on a disk rotating at a constant angular rate of 7.5 rpm immersed in water by injecting colored dye using a syringe connected to a hypodermic needle. The subsequent flow developments were recorded in video form. Stills were extracted from these videos and post-processed with Photoshop into image sequences to illustrate motion on paper. Two types of protrusion with a right angle triangle cross-section were tested; one straight and aligned in the disk’s radial direction, and the other at a 30 degrees angle from the radial direction. It was observed that a coherent vortex was formed aft of these protrusions, and that the formed vortex has a tendency to propagate along the span of the protrusions. However, this propagation is less significant when an angled protrusion was used. It is also found that a flat disk without any protrusion does not produce a coherent vortex at all. This study has achieved its stated objectives of visualizing the flow field and provides recommendations on conducting future work, such as overhauling the experimental setup and testing of different types of protrusions, to further research and developments within this field.
Flow visualization study on a rotating disk with a vortex-trapping protrusion / Ng Dick Son