Beugung von Schallwellen an der kreisförmigen Öffnung im schallharten Schirm

The sound pressure at the central normal behind circular apertures in rigid screens of radii of ρ ₀ = 0.5 λ, 1λ, 1.5 λ, 2 λ, 3 λ and 4 λ, and within the plane of the screens is experimentally investigated. An application of the Kirchhoff theory to these problems supplies two approximate solutions. These are compared with the experimental results, and it is shown that the observed diffraction effects down to a diaphragm radius of half the wave length can be fairly well explained — within the limits of the accuracy of measurements — using the velocity potential derived from the area of the aperture considered to be covered with dipoles.