Effects of end condition and aspect ratio on aerodynamic properties of rectangular sectional model

End condition and aspect ratio of the sectional model are two important influence factors on wind tunnel tests. To investigate the effects of end condition and aspect ratio on the characteristics of aerodynamic force of the sectional models, wind tunnel tests are performed on a stationary B/D=5 rectangular sectional model with various end conditions and aspect ratios. The results indicate that:(1) the aerodynamic force on the rectangular cylinder can be significantly influenced by end condition and aspect ratio; (2) when the length of the cylinder is twice larger than the interference length of end condition, the aerodynamic force distributes in spanwise as an isosceles trapezoid, however, when the length of the cylinder is twice smaller than the interference length of end condition, the aerodynamic force distributes in spanwise as an isosceles triangle. More attentions should be paid to the design on aspect ratio of model for wind tunnel tests. A suitable large aspect ratio of the model may lead to reliable results.