Numerical Investigation On Aerodynamic Performance Of Stratosphere Airship

A stratosphere airship is a kind of aircraft runs at the bottom of the stratosphere layer(20km~50km). As a multi-purpose communicating platform, it has been closely attended around the world for the advantages such as long endurance spot hovering, wide area coverage, and hardly to be detected by radars. The aerodynamic performance analysis is the main content in the overall designing and demonstration of a stratosphere airship. Calculating the aerodynamic force and mastering the changing law of the aerodynamic parameters have a practical significance on the effective control operation, stability analysis and reasonable design of the stratosphere airship. The aerodynamic changing law when the environmental and model parameters vary has been explored in this paper through CFD numerical simulation technique based on a specific airship body shape.Firstly, a brief introduction of the Computational Fluid Dynamics of ADINA is brought in to probe into the basic theory in numerical calculation. The airship aerodynamic simulation is presented based on the establishment of governing equations in computing the flow field around the stratosphere airship together with the turbulent model and boundary conditions. Comparing the CFD simulation with the experimental results obtained from the wind tunnel tests, the numerical method adopted in this paper prove to well reflect the aerodynamic characteristics of the stratosphere airship.Secondly, Simulations aiming at original airship model related to changing law of the aerodynamics when the environmental parameters varies, for example the adjustment of pitch or yaw angle in the high-up air or during the ascend process is performed. Research shows that some regularities on the airship aerodynamics with the variation of the pitch or yaw angle, while the aerodynamic properties seem to be more complicated during ascending. To provide reference for the designing of the airship aerodynamic shape, simulations on the aerodynamic differences with the model parameter varies, such as with or without tails, fineness ratio changes and comparison of the original and the scaled model are also presented.At last, Summarizing the major factors that influence the airship aerodynamics, groups of data has been obtained through computing the aerodynamic drag force with fineness and Reynolds number both differ. A formula related to the drag coefficient is proposed by surface fitting the dataset and then a modified one is put forward considering the effect of the pitch and yaw angle. Both formulas are verified to be applicable to the specific shape in this paper.