An energy harvesting apparatus is described that utilizes hydraulic actuation and creates a continuous, revolving motion of a chain of energy-producing elements within an energy-producing channel (the channel being in the form of a tube, for example). In particular, the arrangement of the present invention is based upon a specially-designed dual-loop channel topology that allows for efficient conversion of a unidirectional flow of a fluid entering the energy-producing channel into a smooth, continuous revolving motion of a chain of energy-producing elements within the channel.