Effect of attack angle on the flow around adjacent circular and rectangular prisms

Seyhan M., Sarıoğlu M., Akansu Y. E.

Ömer Halisdemir Üniversitesi Mühendislik Bilimleri Dergisi, vol.10, no.2, pp.1-7, 2021 (Peer-Reviewed Journal)


An experimental investigation has been carried out to clarify the flow structure around adjacent circular and rectangular prisms. The measurements of hot-wire for Re= 4.1 x 10³, 9.0 x 10³ and 1.5 x 10⁴, lift and drag force for Re = 1.0 x 10⁴, and in addition the flow visualization experiments for Re = 2.3 x 10³ have been performed in the range of 0° ≤ α ≤ 180°. The adjacent bodies consist of a circular cylinder having 9.5 mm diameter and a rectangular prism having 6 mm x 10 mm cross-section attached to the circular cylinder from its short side in all the cases. The hot wire measurement results showed that the Strouhal number has Reynolds number independence for Re = 4.1x10³, 9.0x10³, and 1.5x10⁴. Sudden peaks in St and lift coefficients are obtained for a similar reason that is reattachment of the separated shear layer in the vicinity of α = 60° and 174°. For the adjacent bodies compared with the bare circular cylinder, 40%, and 25% drag reduction is obtained at α = 0° and 174°, respectively. The obtained results show that the variations of lift coefficient, drag coefficient, and Strouhal number are strictly subjected to the attack angle.