Experimental Investigation of Wake Flow of a Hollow Circular Cylinder with Slot at Various Angles of Incidence

Öz

In this study, the flow characteristics and drag coefficients in the wake of hollow circular cylinders with slots were experimentally investigated. The experiments were carried out for the Reynolds number Re = 10 000 based on the cylinder diameter (D=50 mm); three different slot widths were selected as slot ratios w/D = 0.04 (2 mm), 0.16 (8 mm), and 0.20 (10 mm). For each configuration, flow and turbulence statistics in the wake region were obtained by using particle image velocimetry (PIV) technique at 30°, 45° and 60° angles of incidence of the flow. In addition, the drag coefficients of slotted cylinders were measured in the wind tunnel and compared with the bare case. The results show that both the slot ratio and the angle of incidence of the flow affect the flow structure in the wake. It was observed that the drag coefficient values increased with increasing angle of incidence compared to the bare cylinder.

Anahtar Kelimeler

• Slot
• Flow characteristic
• PIV
• Cylinder

Yarık Açılan İçi Boş Dairesel Silindirin Art İzindeki Akışın Farklı Geliş Açılarında Deneysel Araştırılması

Öz

Bu çalışmada, yarıklı içi boş dairesel silindirlerin art izindeki akış karakteristikleri ve sürüklenme katsayıları deneysel olarak incelenmiştir. Deneyler, silindir çapına (D=50 mm) göre belirlenen Reynolds sayısı Re = 10 000 koşulunda yürütülmüş; yarık oranları ise w/D=0,04 (2 mm), 0,16 (8 mm) ve 0,20 (10 mm) olmak üzere üç farklı yarık genişliği olarak belirlenmiştir. Her bir yapılandırma için akışın 30°, 45° ve 60° geliş açıları için parçacık görüntülemeli hız ölçüm (PIV) tekniği kullanılarak art iz bölgesindeki akış istatistikleri ve türbülans dağılımları elde edilmiştir. Ayrıca, rüzgar tünelinde yarık açılan silindirlerin sürüklenme katsayıları belirlenmiş ve yalın silindir kullanımı durumunda elde edilen sonuçlar ile karşılaştırılmıştır. Sonuçlar, hem yarık oranın hem de akışın geliş açısının art izindeki akış yapısını etkilediğini ortaya koymaktadır. Artan geliş açısı ile birlikte sürüklenme katsayısı değerleri yalın silindire göre arttığı gözlemlenmiştir.

Anahtar Kelimeler

• Yarık
• Akış Karakteristiği
• PIV
• Silindir

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