蜂鸟曰常飞行时，羽翼大约每秒拍打十八到八十次，视鸟的大小而定。
In normal flight a hummer 's wings beat about18-80times per second depending on the size of the bird.
它们飞行能力不强，常贴近地面飞行。
就简化的非定常气动力数学模型提出了分析气动弹性时飞行器稳定性的影响的方法。
With simplified unsteady aerodynamic force mathematical model, method of analysis for the effects of aeroelasticity on the dynamic stability of elastic vehicles is established.
试飞飞行员常不得不冒生命危险。
文中在物面无滑移边界条件的基础上施加物面绕体轴的切向速度，通过求解定常ns方程对飞行器滚转进行模拟。
In the paper, the steady NS equation was solved to simulate aircraft roll by adding tangent velocity to no slip wall boundary condition.
而后就简化的非定常气动力数学模型提出了分析气动弹性对飞行器稳定性影响的方法。
A method of analysis of the effect of aeroelasticity on the stability of elastic vehicles by using a simplified mathematical model of unsteady aerodynamic forces is proposed.
大振幅试验，非定常空气动力，空气动力模型，洞壁干扰，动导数仿真，数学模型，模糊逻辑，飞行仿真。
Large amplitude test, Unsteady aerodynamic, Wall influence, dynamic derivative simulating, Mathematic model, Fuzzy logic, Aerodynamicmodeling, Flight simulating.
拦截器在飞行过程中轨控推力以持续定常方式或小脉冲方式施加在垂直视线的方向，目标具有一定的机动能力。
The interceptor had sustain constant thrust or impulsive thrust perpendicular to the line-of-sight during the flight, and the target was maneuverable.
可以提供更详细的多学科计算流体动力学的非定常空气动力学过程的认识，涉及现代制导武器系统机动飞行。
Multidisciplinary computations can provide detailed fluid dynamic understanding of the unsteady aerodynamics processes involving the maneuvering flight of modern guided weapon systems.
研究了在常推力作用下，两个空间飞行器的固定时间最省燃料交会问题。
The problem of optimal bounded thrust time fixed rendezvous of two spacecraft is investigated in this paper.
研究了在常推力作用下，两个空间飞行器的固定时间最省燃料交会问题。
The problem of optimal bounded thrust time fixed rendezvous of two spacecraft is investigated in this paper.
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