A、随边0.4R
B、随边0.7R
C、导边0.4R
D、导边0.7R
第1题:
A、在螺旋桨工作时发出的“嗡嗡”的响声
B、导边涡流激振力引起的桨叶振动
C、实质上是共振
D、随边0.4R以外部位的涡流引起的振动频率与桨叶固有频率接近所致
第2题:
第3题:
在鱼洗实验中,下列哪个说法是正确的? In the fish washing experiment, which of the following statements is true?
A.当鱼洗器壁的振动频率越来越接近于鱼洗固有频率时,产生共振现象; Resonance phenomenon occurs when the vibration frequency of the wall of the fish washer is closer and closer to the natural frequency of the fish washer;#B.当鱼洗器壁的振动频率大于鱼洗固有频率时,产生共振现象; Resonance phenomenon occurs when the vibration frequency of the wall of the fish washer is greater than the natural frequency of the fish washer;#C.当鱼洗器壁的振动频率小于鱼洗固有频率时,产生共振现象; When the vibration frequency of the fish第4题:
直升机诱导旋转阻力产生的原因是()
A.旋翼向下排压空气使空气加速向下流动
B.空气与旋产生摩擦
C.桨叶前缘阻挡空气和后缘涡流区的影响
第5题:
66、在鱼洗实验中,下列哪个说法是正确的? In the fish washing experiment, which of the following statements is true?
A.当鱼洗器壁的振动频率越来越接近于鱼洗固有频率时,产生共振现象; Resonance phenomenon occurs when the vibration frequency of the wall of the fish washer is closer and closer to the natural frequency of the fish washer;###SXB###B.当鱼洗器壁的振动频率大于鱼洗固有频率时,产生共振现象; Resonance phenomenon occurs when the vibration frequency of the wall of the fish washer is greater than the natural frequency of the fish washer;###SXB###C.当鱼洗器壁的振动频率小于鱼洗固有频率时,产生共振现象; When the vibration frequency of the fish