Experiments performed summer 1976 in an anechoic chamber at NASA Langley Research Center consisted of (1) diffraction around screen from point source not necessarily far from edge, (2) such diffraction when air is blowing parallel to screen sides with diffracting edge as trailing edge, (3) diffraction of noise from a jet of air exiting on one side of a thin screen, and (4) diffraction of sound around a barrier with curved top with radius of curvature larger or comparable to an acoustic wave‐wavelength. These experiments were prompted by problems of assessing effects on aircraft noise when engines are mounted above wings. Accompanying theoretical work consisted of (1) generation of a convenient rapidly convergent numerical integration method for computation of Green's function given arbitrary sources and listener locations near a rigid wedge and (2) extension of Candell's solution of plane wave diffraction by screen in presence of ambient air flow to the point source case. [Work supported by NASA Langley Research Center.]