The flow around and behind a permeable wall cube set on a flat plate turbulent boundary layer has been investigated experimentally. Eight kinds of cubes, each different in the value of open area ratio, have been used in this experiment. Flow patterns are split into two cases considering the value of open area ratio β=0.32 to 0.40 as a boundary. One of them is the case for which the separation bubble causes behind a cube, and the other is the bubble is not observed. In the former, the separation bubble behind a cube moves downstream as the open area ratio increases. The tendency of spread of the wallwake region is characterized by the value of open area ratio in both x-y plane and x-z plane. These phenomena seem to be dependent on the strength of secondary flow found in the flow field behind a permeable wall cube.
A pulsed molecular beam source with an electromagnetic valve controlled by a microcomputer has been developed. Relative intensities and velocity distributions of the molecular beams from the source with a convergent and a convergent-divergent nozzles are measured. For these measurements a data acquisition system using the microcomputer has been also developed. For the convergent nozzle the measured beam intensity and speed ratio are consistent with theoretical considerations and the existing data. For the nozzle with a divergent section, beams of about 20 times larger in intensity and two times in speed ratio compared with those for the convergent one are obtained.
A theory is presented to show simply the essential effect of sweep angle on divergence and aileron reversal. For this purpose, several simplification assumptions are introduced such as high aspect ratio, strip theory of aerodynamics, effective wing root and tip, assumed mode shapes for bending and torsion, etc. Thus a kind of theory for "typical section" is developed. The result shows that the divergence speed would be increased and decreased by sweep back and forward, respectively-as well-known. But for aileron reversal, the result seems not to agree with descriptions in usual text books. The result obtained here suggests that the reversal speed increases irrespective of sweep back or forward, while the lift due to aileron angle increases and decreases for sweep forward and back, respectively.