Aerodynamic forces acting on two square prisms placed vertically in a turbulent boundary layer: Fid-Bau Portal

Aerodynamic forces acting on two square prisms placed vertically in a turbulent boundary layer

Sakamoto, H. / Haniu, H.

Abstract The characteristics of the time-mean and fluctuating forces acting on two square prisms placed vertically in various arrangements in a turbulent boundary layer are described. Firstly the behavior of the aerodynamic forces on the two prisms in a tandem arrangement have been investigated. The results are summarized in several figures from which one can obtain the time-mean drag, the fluctuating drag, the fluctuating lift and the Strouhal number for the various spacings between the two prisms. Phase relationships between the fluctuating lift of the two prisms are presented and discussed. The phase shift between the fluctuating lift acting on the two prisms has been found to be proportional to the distance between the two prisms. Secondly the behavior of the aerodynamic forces on the two prisms in a side-by-side arrangement has been similarly investigated. In particular, the variations of the flow patterns with the spacing between the two prisms are discussed in detail, based on the Strouhal number and the cross correlation between the fluctuating pressures acting on the two prisms. Lastly, the characteristics of the fluid forces acting on the downstream prism and the flow pattern around it are described for the case of a staggered arrangement. The results are presented as equi-line diagrams of the time-mean drag and lift, the fluctuating drag and lift and the Strouhal number of the downstream prism for various relative locations. From the unique variations of the fluid forces and the Strouhal number of the downstream prism, it has been found that the distributions of the fluid forces can be classified into three regions and that the Strouhal number can be classified into four regions.