Airship Turn Performance Estimated From Efficient Potential Flow Panel Method

Abstract

A first-order potential flow panel method is used in the present work to calculate aerodynamic yaw torques and other parameters involved in the turning performance of a stratospheric lighter-than-air airship. A specific mesh is generated to model the airship geometry in order to solve the Laplace potential flow equation by a sum of source and doubled distributions on the boundary, using a mix of Neumann and Dirichlet boundary conditions. As a result, it is possible to simulate the effect of the rudder and elevons within their angular range at different flight conditions. Air flow rotation is included in the boundary conditions to simulate airship yaw rate. Thus, the result of the model includes not only yaw momentum but also its derivative with respect to yaw rate and the lateral force. They are contrasted with a series of tests carried out in a wind tunnel for a stratospheric airship model and with the literature. Despite of the simplicity of the potential method (5 s execution for a 6000-cell mesh) compared to a more complex CFD simulations, the conclusions demonstrate that the correlation between numerical and experimental data is high enough to provide valuable performance insights during the design process, showing a considerable reduction of the necessary computational resources. A 30 m ECOSAT model with proper fins can turn with a steady radius of 50 to 60 m.