Abstract: According to the invention, a device for the generation of eddies creates or destroys eddies in a flowing medium in a particularly simple manner, with particularly low energy requirement with the lowest possible pressure drop, whereby the device comprises one or more profiles, for the flowing medium to flow around, which are provided with an external drive for a periodic movement relative to the flowing medium with an angular frequency ?. The profiles are thus periodically displaced with an angular frequency ? by an external drive.

Abstract: According to the invention, a device for the generation of eddies creates or destroys eddies in a flowing medium in a particularly simple manner, with particularly low energy requirement with the lowest possible pressure drop, whereby the device comprises one or more profiles, for the flowing medium to flow around, which are provided with an external drive for a periodic movement relative to the flowing medium with an angular frequency ?. The profiles are thus periodically displaced with an angular frequency ? by an external drive.

Abstract: A pole coil wherein improved heat transfer at cooling fins thereof is achieved and includes cooling fins which are subdivided in the longitudinal direction into short portions which are bent out so that they are disaligned with each other. The pole coil is suitable for electrical machines and apparatus and especially for the revolving excitation windings of synchronous electric machines.

Abstract: A cooling arrangement is provided for an electric generator of an underwater power plant contained in a body wherein a coolant is circulated for cooling the generator. The cooling arrangement includes a cowl that covers the end-face of the generator and forms a portion of the body. The outer surface of the cowl is exposed to the turbine water and the inner surface of the cowl defines a path for conducting the coolant therealong for recooling the coolant. A plurality of cooling fins are provided and each of the fins has two end-portions bent toward each other to give the fin a hook-like configuration. Each fin is fixedly mounted to the inner surface of the cowl at one of the end-portions thereof. The fins are short relative to the length of the path.