A water turbine constructed on the water turbulence or whirlpool principle is capable of utilizing very small sources even for untapped water, and it is highly suitable for the closed circuit production of electrical energy. The non-monotonic distribution of the radial velocity component is important for the onset of the driving force of the angular instability. This instability and the existence of the radial fluid motion give rise to the angular volume force. The strong gradient of entropy in the boundary layer of the inner rotating conical cylinder is a dominant source of vorticity. The solution presented as a result of the theoretical analysis includes discussion and comparison with rough preliminary experimental data. The rotating fluid action is obviously of interest for further research. An improvement in efficiency is the genuine motive for further research. (C) 2012 Elsevier Ltd. All rights reserved.