The structural configuration of fin propeller complex and lift resistance characteristics in different conditions are discussed.
并研究了鳍桨组合体的结构形式，不同情况下的升、阻力特性；
2
Period characteristics of radiated noise at high frequency is investigated by a method based on short time Fast Fourier Transformation, and propeller speed is estimated.
用短时傅立叶分析的方法研究了辐射噪声在高频段时频变化的周期性，估计了目标的螺旋桨转速。
3
The vibration characteristics of propeller blades have been investigated by using experimental modal analysis technique.