It is common that bluff bodies form complex wake structures and act on themselves with significant influence on aerodynamic forces. A square cylinder was studied as a typical model that makes complex flowfields. A magnetic suspension and balance system (MSBS) was used to support the model with magnetic forces and eliminate the influence of mechanical supports on the flowfield of wind-tunnel testing. The aerodynamic forces and base pressure of the square cylinder models with fineness ratios (L/D) of 1.0, 1.2, 1.68, and 2.0 were measured using the MSBS. The employed Reynolds numbers were from 0.5 × 10 5 to 1.3 × 10 5 . The drag coefficients were independent of the Reynolds number Re and could be divided into two regions between L/D = 1.2 and 1.68. The base pressure coefficient decreased monotonically from 1.0 to 1.68. The drag did not significantly change for L/D = 1.0 and 1.2 with angles of attack from -2 to 2 deg. In contrast, it quadratically increased from L/D = 1.68 and 2.0. The lift–curve slopes were negative from L/D = 1.0 to 1.2 and positive from L/D = 1.68 to 2.0, confirming the reversal. The moment–curve slopes were negative for all fineness ratios. Notably, these changed linearly from L/D = 1.0 to 1.2 and nonlinearly from L/D = 1.68 to 2.0. The visualization test using the surface-oil-flow method revealed that the square cylinders had a reattachment position near X/D = 1.5 for L/D = 1.68 and X/D = 1.8 for L/D = 2.0 . This suggests that the reversal of the lift–curve slope was caused by reattachment.


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    Titel :

    Aerodynamic Characteristics of Magnetically Suspended Square Cylinders with Low Fineness Ratio


    Beteiligte:
    Okuizumi, Hiroyuki (Autor:in) / Makino, Rintaro (Autor:in) / Horiguchi, Masatoshi (Autor:in) / Saito, Yuji (Autor:in) / Sawada, Hideo (Autor:in) / Konishi, Yasufumi (Autor:in) / Obayashi, Shigeru (Autor:in) / Asai, Keisuke (Autor:in) / Nonomura, Taku (Autor:in)

    Erschienen in:

    Journal of Aircraft ; 62 , 3 ; 702-708


    Erscheinungsdatum :

    01.05.2025




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch