1.Дайте русские эквиваленты следующим английским словам и словосочетаниям, которые являются ключевыми для данного текста:

Capacity, head, power, suction lift, create, to provide flow, to transmit a force, restriction, obstruction, fittings, to impose smth, a continuous supply of fluid, available, atmospheric pressure, the force of gravity, supplement, volumetric output, to rate,, rotary drive, displacement, revolution, leakage, slippage

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Historical Background

The emergence of hydraulics as a science followed the discovery of certain laws and the elucidation of a number of problems, connected with the equilibrium and motion of fluids.

In the second half of the 15^th century Leonardo da Vinci studied questions of hydraulic engineering. In his paper “On the flow of water and river structures” he set forth his observation and experience, gained in the construction of hydraulic installation in Milan, Florence and other places. In 1612 Galileo’s paper, which contained the fist systematic study of fundamentals of hydrostatics, appeared. In 1643 Galileo’s pupil Torricelli enunciated the law of free flow of liquids through orifices. In 1650 the law of pressure distribution in a liquid, known as Pascal’s law, was discovered. The important law of friction in a moving fluid was formulated in approximate form by Isaac Newton, to him also goes the credit of introducing type concept of fluid viscosity and of laying the foundation of the theory of hydrodynamic similarity.

These however were isolated law and problems, and until the middle of the 18^th century there existed no comprehensive science of the behavior of fluids. Daniel Bernoulli and Leonardo Euler laid the theoretical foundations of fluid mechanics and hydraulics as a science in the 18^th century.

In 1738 in his “Hydrodynamics” Bernoulli formulated the fundamental law of fluid motion giving the relation between pressure, velocity and head of a fluid.

Euler is credited with the general laws of work for all rotodynamic hydraulic machines (turbines, centrifugal pumps and fans) and with laying the foundation of theory of buoyancy. In his work Euler kept in contact with the great Russian scientist Lomonosov and was undoubtedly influenced by him. Lomonosov is known to have studied many physical problems having a direct bearing on the flow of liquids and gases and showed considerable interesting engineering hydraulics. The works of Bernoulli, Euler, and Lomonosov concluded the first period in the development of hydraulics by laying its foundation as a science.

The second period, embracing the latter part of the 18^th and most of the 19^th centuries, is characterized chiefly by the accumulation of experimental data on the flow of fluids in a pen and closed channels.

In the next period, commencing at the turn of the century, the theoretical basis of hydraulics was further extended by taking into account the viscosity of fluids, the theory of similarity and other theoretical and practical problems were elaborated. This period in the development of hydraulics, as of other engineering discipline, gained impetus from the rapid expansion of the productive forces and technological progress. It is associated with the names of George Stokes (1819-1920), Osborne R. (1824-1912), Nicolai Joukovski (1847-1921), Petrov (1836-1920) and others. G. Stokes laid the foundation of the theory of fluid flow taking into account viscosity and elaborated other theoretical problems.

O. Reynolds was the first to study turbulent flow, the most complex type of fluid motion.

In Russia professor Petrov’ s classical experiments proved the validity of Newton’s law of friction in a fluid, till then treated as a hypothetical. This served as the basis for the theory of machine lubrication which played an important part in the further investigation of the question.

Of tremendous importance for the development of hydraulics were the works of the great Russian scientist N. Joukovski. He published several papers on hydraulics which brought him world-wide fame.

His major work in the field of so-called water hammer in pipelines, was a cause of many breakdowns. Not only did he developed the theory of complex phenomenon caused by a sudden closure of a valve, turbine gate or faucet, but also carried out many experiments at the Moscow waterworks which confirmed his theory and ensured its practical application. The treaties were soon translated into many languages and Joukovski’s water-hammer theory is today included in all textbooks on hydraulics.

Joukovski laid the foundation of the theory of flow of ground water. He studied problems of liquid flow through orifices, the theory of lubrication, velocity distribution in water mains the reaction of fluid jets and vibration of fluids and he established the analogy between wave formation on a liquid surface and pressure jump in air at supersonic speed. Joukovski can be regarded as the founder of the school in hydraulics which combines theoretical and experimental findings and carries research to the stage where it yields practical results.

This combination of methods of theoretical fluid mechanics and experimental hydraulics and the growing tendency towards the merging of the two formerly isolated disciplines with their entirely different methods is one of the characteristic features of modern hydraulics.

The construction of huge hydroelectric plants, canals and pipelines and the development of hydraulic machinery confronted Russian scientists and hydraulic engineers with more new problems which had to be studied and solves for practical needs.

Russian scientists and engineers have achieved marked success in hydraulic engineering. The great advance in this branch of Russian engineering is reflected in the design manufacture of turbines for the world’s biggest hydroelectric stations.

The successful launching of manned spaceships presents another spectacular example of the great achievements of Soviet and Russian science. Their orbiting required powerful multistage rockets, in the construction of which hydraulic engineers took part together with scientists and engineers of other fields. 5675

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