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 to . The drag coefficients were independent of the Reynolds number Re and could be divided into two regions between and 1.68. The base pressure coefficient decreased monotonically from 1.0 to 1.68. The drag did not significantly change for and 1.2 with angles of attack from -2 to 2 deg. In contrast, it quadratically increased from and 2.0. The lift–curve slopes were negative from to 1.2 and positive from to 2.0, confirming the reversal. The moment–curve slopes were negative for all fineness ratios. Notably, these changed linearly from to 1.2 and nonlinearly from to 2.0. The visualization test using the surface-oil-flow method revealed that the square cylinders had a reattachment position near for and for . This suggests that the reversal of the lift–curve slope was caused by reattachment.
Aerodynamic Characteristics of Magnetically Suspended Square Cylinders with Low Fineness Ratio
Journal of Aircraft ; 62 , 3 ; 702-708
2025-05-01
Article (Journal)
Electronic Resource
English
Engineering Index Backfile | 1960
|