Abstract: A wall having a surface in contact with a fluid, has a surface configuration which reduces drag if there is relative movement between the surface and the fluid. The wall is made of metal or of fiber composite material in such a way that sharp edged or fine ridges and grooves between the ridges are formed as integral surface components of the wall structure for simplifying the construction, reducing the weight, and increasing the useful life of structures having such walls.

Abstract: A supercritical wing of the variety in which the compression shock is stabilized is being improved by providing a suction device, substantially along the entire wing span, right at the chord station of the upper-wing surface where intercepting the sonic line. Specific rules concerning the suction and suction slit are given. A small chord station range may be covered by a movable slot or several parallel-running slots. The surface contour may be modified right at a slot to, thereby stabilize the compression shock further. The invention shifts buffet onset to larger off-design Mach numbers and angles of attack.