While the flutter self - excited loads of a bluff section has a quality of obvious nonlinearity . and the application of flutter derivatives to self - excited loads of the bluff section is close to a linear relationship . 5 而钝体断面的颤振自激力高次谐波分量较大,具有较明显的非线性响应特征,验证了用颤振导数表示钝体的自激力只是一种线性近似。