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【单选题】
The turbulent drag is ____ to the laminar drag.
A.
2 to 4 times
B.
3 to 5 times
C.
4 to 6 times
D.
5 to 7 times
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【多选题】The main methods of laminar flow control include: ____.
A.
Changing the wing’s configuration
B.
Breath air at the wing’s leading edge
C.
Breath air at the wing’s lower surface
D.
Breath air at the wing’s upper surface
【单选题】Which of the following is wrong about the vortex generator? ____.
A.
Its shape looks like a small triangular wing panel.
B.
Can suppress the airflow separation and reduce the drag.
C.
Can enhance the lift of the wing.
D.
Placed on engine nacelles and can suppress the airflow separation of nacelle.
【多选题】Main methods of suppress the airflow separation are: ____.
A.
Using vortex generator.
B.
Using air blowing control at separation position
C.
Launch a high-speed jet at the leading edge of the wing.
D.
Control the angle of attack of the wing.
【单选题】The vortex lift generated by the leading-edge vortex can reach ____ of the total lift.
A.
More than 10%
B.
More than 20%
C.
More than 30%
D.
More than 40%