Yoshimasa Furuya

Experiments on Scattering of Molecular Beams on Polycrystalline Platinum Surfaces

A high-intensity molecular beam apparatus has been constructed and the spatial distributions of argon and nitrogen beam scattered on polycrystalline platinum surfaces were measured. A skimmer-orifice having a new configuration, and related measuring devices were constructed in order to carry out an accurate measurement of the flux distribution. In relation to the flux distribution of reflected molecules, diffuse scattering patterns are obtained for surface temperatures lower than 100°C, while the flux distributions obtained at surface temperatures higher than 100°C can be explained by the simple superposition of diffuse and lobular scattering patterns. The pattern of the lobular reflection qualitatively agrees with the hard-cube theory.

An Experimental Investigation of the Skewed Boundary Layer on a Rotating Body (2nd Report)

Experiments were carried out on velocity distributions of the three-dimensional boundary layer on a cylindrical half body with a hemispherical nose rotating in axial stream. When the body remaind stationary, there was a separation bubble just behind the hemisperical nose. This separation bubble disappeared when the ratio of peripheral velocity of the cylinder to the reference main stream increased up to about 0.44, because of the additional acceleration produced by centrifugal force at the nose. This had also an effect on the polar plots of laminar boundary layer to modify the velocity profiles in the meridian direction. Momentum thicknesses obtained from the experiment agreed well with results of two theories. As in case of two-dimensional flow, boundary layer separation occurs far up-stream from the point which is predicted by the theory of the 4-th order polynominal velocity profiles.

Effect of Surface Roughness on the Velocity Defect Law

The logarithmic plot of the velocity defect law of rough‐surface flat plates is slightly higher than that of smooth plates. This result is ascribed to the fact that the shear stress at the wall preserves its value at a larger distance from the wall.