901 publications from this institution
The purpose of this paper is to examine how rib configurations and spar configurations influence flying wing stability. Flying wing aircraft exhibit enhanced flutter characteristics when stresses flow smoothly through the wing. We prevent stress strangulation through spar cross-sections by changing the configuration in the plunge direction. We employ and develop computer programs Gmsh, Variational Asymptotic Beam Sectional Analysis, MATLAB scripts, and Nonlinear Aeroelastic Trim and Stability of High Altitude Long Endurance Aircraft. The configurations are designed by considering the same material, mass, and flight conditions. The results indicate that the design with the smoother stress distribution through the wing has a higher flutter speed. It is shown that the σ11 and Von-Misses stress distributions have an important effect on the stability of a flying wing aircraft.
This note describes an experimental study of the damaging effect of hydrogen bubbles on the effectiveness of the thymol blue velocity measurement method. Specifically, we document the effect of flow velocity, cathode voltage, and cathode diameter on bubble formation and the quality of the thymol blue pattern. The time of bubble damage, i.e., the interval preceding the destruction of the blue pattern, was measured and reported as a function of flow velocity, cathode voltage, and cathode diameter.
