| 摘要 |
<p>1,007,996. Supporting pipes. SOC. D' ETUDE DU TRANSPORT ET DE LA VALORISASATION DES GAS NATURELS DU SAHARA S.E.G.N.S. Sept. 26, 1963 Oct. 8, 1962], No. 37898/63. Heading F2P. The action of transverse currents on an immersed pipe or group of pipes is decreased by placing the pipe within a casing of polygonal section. The upper and lower faces of the casing may be put into mutual communication by means of spaced passages 7. The profile of the casing 2 is trapezoidal with its base 4 resting on the sea bed. The base has slight projections 4b, 4c which reduce the tendency of the casing to slide on the sea bed because of transverse currents, e.g. F. Metal lattice strip 6 covers the top part of the casing to give the surface a roughness which creates turbulence that tends to divert upwards the current leaving the surface and so reduce the lowering of pressure on the side of the casing remote from that subject to the currents F. Vents 7 are situated between the two pipes la, 1b, protected by the casing and, by putting the top and bottom surfaces in communication with each other, decrease the pressure gradient between them. Thus the lattice 6 tends to reduce drag and the vents tend to reduce lift.</p> |
