平流层飞艇的附加质量及其对飞艇运动的影响

采用Hess-Sm ith方法对三维物体在流体中运动时的速度势进行数值计算,并用球体的理论值与之比较,验证了程序的正确性,在此基础上编写附加质量的计算程序,并与椭球的理论值进行比较,验证了该程序的可靠性。通过建立飞艇六自由度运动方程,利用不同的附加质量值计算飞艇的运动,得到了不同的运动参数值,依此判断附加质量值对飞艇运动有较大影响,不能随意假设。通过对飞艇运动状态参数的分析,指出飞艇在无控状态下是不稳定的,因此需要采用控制。

Added Mass to Stratospheric Airship and Its Effect on Motion

A computation program for calculating potential of an arbitrary threedimensional body maneuvering in fluid is developed by the Hess-Smith method.The program's veracity has been certified by comparison with the theoretically calculated potential of sphere.According to the above mentioned theory,a computation program for calculating added mass to an arbitrary three-dimensional body maneuvering in fluid is developed by the Hess-Smith method.The program's reliability has been certified by comparison with the theoretically calculated added mass of ellipsoid.And the different parameters of airship motion are achieved with the different added mass according to the six-degree-of-freedom dynamic equation.This result shows that the added mass has a considerable effect on airship motion and the added mass may not be assumed arbitrarily.Then a conclusion is made that the motion of the airship is unstable on the condition of little disturbance and the airship needs control.