A solution of three-dimensional axi-symmetrical incompressible in viscid irrotational flow taking place between two equipotential planes perpendicular to the axis is given, and is the general solution. This type of flow corresponds to that in the electric tank in which the technique employed is by now well known. The solution' is equivalent to expressing the axial velocity distribution as a Fourier cosine series, and since any such distribution may be so expressed to which corresponds a unique flow-pattern elsewhere, the solution is general.nThe design of contracting channels between equipotential planes is discussed, and several examples given demon¬strating the method. Channels so derived are, strictly, periodic, but their suitability for wind tunnels in which parallel walls are faired into the contraction is discussed. This method of design can produce a very great variety of shapes;it would, of course, be more satisfactory to design infinite contracting channels, but this is extremely difficult to do in three dimensions.
展开▼
