Numerical aerodynamic investigations on stratospheric airships of different tail configurations
Numerical investigations on stratospheric airships of different tail configurations are conducted based on the Reynolds-averaged N-S equations and k-ω SST turbulent model in the condition of the same volume and total area of the tails. The influence of tail configurations on the force and moment characteristics as well as flow phenomena on both hull and fins are analyzed. In particular, the hull-fin mutual interference effect is discussed compared to the bare hull performance. It is found that a cross-shaped tail produces a superior lift characteristic and stability at high angle but greater drag due to horizontal fins, both in pitch and yaw channels than the inverted Y and X shaped tail. The hull-fin interference generates additional hull lift, drag and an offsetting moment and causes side edge separation on the suction side of horizontal (side) fins in the cross (inverted Y and X shaped) tail configuration. The inverted Y-shaped tail provides the greatest interference drag. These investigations serve to provide references for airship configuration design.
Wind Pressures on the Akron Airship Dock
THE Airship Dock at Akron, Ohio, Fig. 1, a hangar of unique dimensions and design, has been an interesting object for the study of wind pressure distribution on buildings. Its design features such as the vaulted roof and the vanishing "orange-peel" doors were dictated by airship operating considerations. At first glance one would expect that such liberal concessions to the demands of the operator and radical departure from conventional building design might entail a great sacrifice in cost. Fortunately, the contrary is the case. The vaulted building is a more efficient structure than one covered with a flat or saddled roof. The vanishing "orange peel" type doors are much more easily braced because wind loads on them are of little significance, whereas flat wing doors require huge bracing structures to hold them erect when open in any wind. The same advantage is reflected in the size and simplicity of the mechanism with which they are operated for opening and closing.
A study of effects of viscosity on flow over slender inclined bodies of revolution
From Summary: "The observed flow field about slender inclined bodies of revolution is compared with the calculated characteristics based upon potential theory. The comparison is instructive in indicating the manner in which the effects of viscosity are manifest. Based on this and other studies, a method is developed to allow for viscous effects on the force and moment characteristics of bodies. The calculated force and moment characteristics of two bodies of high fineness ratio are shown to be in good agreement, for most engineering purposes, with experiment."