Modeling of stratosphere airship
The dynamics and kinematics model is very important for the analysis of stability, manipulation and control of stratosphere airship. A full modeling approach that includes the computation of aerodynamics of airship and the added mass for the nonlinear dynamics simulation of stratosphere airships is proposed in this paper. In this approach, the aerodynamics of airship is calculated based on a panel method, an engineering estimation and theory approach. A new numerical method for calculating added masses of airship is developed by using the CFD method. This model can simulate the motion of stratosphere airships quickly and accurately.
Aerodynamic Estimation for Stratosphere Airship
An efficient aerodynamic calculation method,based on a panel method and engineering estimation approach was used.The aerodynamic forces of airship are divided into two part: the aerodynamic forces of airship body and fins.Every part is composed of the linear and nonlinear aerodynamic forces.The linear aerodynamic forces of airship hull were calculated in terms of Munk airship theory.The linear aerodynamic forces of airship hull were calculated by Allen viscous cross flow theory.The fins linear aerodynamic forces were calculated by approach of panel method.The nonlinear aerodynamic forces of fins were calculated by Polhamus-Lamar suction analogy method.The interference of body and fins are included in this model.It shows that the model can efficient estimate the aerodynamic forces of airship through the comparison of results between computation and experiment.
Stability Analysis of a Tethered Aerostat
This paper presents a dynamics analysis of a streamlined aerostat tethered to the ground by a single tether. A nonlinear dynamics model of this system is e rst assembled. The tether is modeled using a lumped mass approach, and the viscoelastic properties of the tether are included. The aerostat is modeled using a component breakdown approach. The dynamics equations of the cable and aerostat are then assembled into a single system of nonlinear differential equations. A linearization of this system is then performed using a e nite difference approach. The resulting linear equations of motions are decoupled into longitudinal and lateral subsets. The stability properties of each subset is then studied as a function of wind speed. The effect of varying tether length is also investigated.