The ground testing of large antenna deployment is important in verifying it's deployment capability in geostationaly orbit. But the exact simulation of deployment motion by ground testing is significantly inhibited due to prominent gravitational or atmospheric effects on deployment motion. As a part of verification activity, the object of this study is to estimate these ground effects on deployment motion quantitatively and to define the best method for ground deployment tests. Ground testing equipment was constructed in such a way that gravity effects were canceled by means of suspending reflector from the point at 10m high. Analytical results with careful consideration to friction torque and air drug torque obtained in the simple model tests closely corresponding to the results of ground testing for actual antenna reflector.
It is the purpose of this study to obtain solutions, which contain complete discontinuities of shock waves, of the potential equations for transonic airfoils using numerical techniques. For iterative calculations, the potential equations are transformed into a more convenient form of simultaneous equations with two variables of velocity potential and Mach number. The solutions with the complete discontinuities of shock waves satisfying Prandtle's relationship are obtained by the iterative calculations without divergencies or hight frequencies under a grid system in the physical plane. Numerical results of the present techniques and of another methods for the transonic flow over airfoil of NACA 0012 with shock wave are used as test cases of comparisons.
This paper describes an experimental study of the changes of vortices formation and turbulent wake from a circular cylinder with the slenderness of cylinder, placed on a ground plane. The experiment was carried out in an N. P. L. blow down type wind-tunnel having a working section of 500mm×500mm×2, 000mm in size at the Reynolds number 2.5×104 to 4.7×104. The surface-pressure distributions on the circular cylinder were measured and the drag coefficient was determined from them. The vortices of two kinds generated in the flow-field around a circular cylinder have also been observed and the velocity defects and turbulent intensities in the turbulent wake behind a circular cylinder were measured. Consequently, it is found that the flow pattern changes rapidly from H/D=4, while the shedding vortices change from arch type to Karman type.
The present paper contains an experimental research on some aerodynamic performance of Lippisch-Type GEW (Ground Effect Wing). This type has a reverse-Delta wing with some cathedral angles (C. A.) along the leading edge. Based upon the comparison between experiment I (C. A.=16.3°) and II (C. A.=8.1°), the following conclusions can be drawn. (1) There are some increments of L/D caused from the ground effect both in experiment I and II, but the latter has higher CL than the former. It is caused from modification of the model I. (2) The horizontal tail has no influence to flight in ground effect but out ground effect.