This paper presents the measurements of force coefficients and Strouhal numbers (St) on four cylinders in a square configuration at subcritical Reynolds numbers (Re) using a piezo-electric load cell in a wind tunnel. Six spacing ratios (L/D) varying from 1.69 to 3.83 and 13 angles of incidence ranging from 0 deg to 180 deg at a 15 deg interval covering all orientations were investigated. With the help of a laser-induced fluorescence visualization technique, it is found that the variation of forces and Strouhal numbers with L/D are governed by three distinct flow patterns. They are: (a) free oscillations of shear layers and vortex formation at large L/D; (b) reattachment of shear layer or shielding flow for intermediate L/D and (c) narrow gap flows for small L/D. Two major causes for large fluctuating forces are discussed in this paper and the force results are compared with other measurements. It is concluded that the flow patterns, i.e., the development and the interferences of the free shear layers and the distribution of the wake vortices of the cylinders play a key role in the variation of the forces and shedding frequencies. Consequently, the downstream cylinders are usually subjected to more serious fluctuating forces under the influence of unsteady wake vortices. Also, the upstream cylinders normally experience larger mean drags than the downstream ones.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Force coefficients and Strouhal numbers of four cylinders in cross flow


    Weitere Titelangaben:

    Kräftebeiwerte und Strouhal-Zahlen für eine Anordnung aus vier quer angeströmten Kreiszylindern


    Beteiligte:
    Lam, K. (Autor:in) / Li, J.Y. (Autor:in) / So, R.M.C. (Autor:in)


    Erscheinungsdatum :

    2003


    Format / Umfang :

    20 Seiten, 21 Bilder, 2 Tabellen, 44 Quellen




    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch




    Strouhal numbers of rectangular cylinders

    Okajima, A. | Tema Archiv | 1982


    Strouhal numbers for the hypersonic wakes of spheres and cones

    FLORSHEIM, B. H. / GOLDBURG, A. / WASHBURN, W. K. | AIAA | 1965



    Unsteady heat transfer from a sphere at low Reynolds and Strouhal numbers

    BAYAZITOGLU, Y. / ANDERSON, C. / COHEN, R. et al. | AIAA | 1993


    Effects of strouhal numbers on asymmetric vortices control using plasma actuation

    Long, Yuexiao / Li, Huaxing / Meng, Xuanshi et al. | AIAA | 2018