This collection of articles will be of interest to scientists in the field of hydraulics and aerodynamics who study questions of the mechanics of movement of liquid and gas, since it contains an analysis of the little-researched hydrodynamic effect that arises when the flow of a moving substance (liquid or gas) is accelerated and the principles of the sustained manifestation of this effect in the liquid are inferred. On the basis of the effect described, the technology for highly-effective free-flow hydraulic turbines is developed and the book cites the working principle for turbines of this new type of construction which make use of this effect, which could in the future become an alternative to existing free-flow turbines and traditional hydropower. It is recommended that hydropower engineers, designers and specialists from who are designing their own models of hydraulic turbines for mini and micro hydropower stations acquaint themselves with this material. An article analyzing the possibilities for using the energy potential of Lake Sarez in the Pamir Mountains, which presents a natural hazard to several states in the Central Asian region, is also contained in the collection.