Everything about Hydraulics totally explained
:
For the mechanical technology, see hydraulic machinery and hydraulic cylinder
Hydraulics is a topic of science and
engineering dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of
fluid power.
Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the
engineering uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe
flow,
dam design,
fluid control circuitry,
pumps,
turbines,
hydropower,
computational fluid dynamics, flow measurement, river channel behavior and erosion. However if used incorrectly, hydraulic instruments can result in weird occurrences because of the nature of high pressure fluids.
The word "hydraulics" originates from the
Greek word
ὑδραυλικός (
hydraulikos) which in turn originates from
ὕδραυλος (
hydraulos) meaning
water organ which in turn comes from
ὕδωρ (
hydor, Greek for
water) and
αὐλός (
aulos, meaning
pipe).
History
Earliest masters
The earliest masters of this science were
Ctesibius (flourished c. 270 BC) and
Heron of Alexandria (c. 10–80 AD) in the
Greek-
Hellenized West. Heron describes a number of working machines using hydraulic power, such as the
force pump, which is known from many Roman sites as having been used for raising water and in fire engines, for example.
China
In
ancient China there was
Sunshu Ao (6th century BC),
Ximen Bao (5th century BC),
Du Shi (circa 31 AD),
Zhang Heng (78 - 139 AD), and
Ma Jun (200 - 265 AD), while medieval China had
Su Song (1020 - 1101 AD) and
Shen Kuo (1031 - 1095). Du Shi employed a
waterwheel to power the
bellows of a
blast furnace producing
cast iron. Zhang Heng was the first to employ hydraulics to provide motive power in rotating an
armillary sphere for
astronomical observation.
Sri Lanka
In ancient
Sri Lanka, the
Sinhalese used hydraulics in many applications, in the ancient kingdoms of
Anuradhapura and
Polonnaruwa. The discovery of the principle of the
valve tower, or valve pit, for regulating the escape of water is credited to Sinhalese ingenuity more than 2,000 years ago. By the first century A.D, several large-scale irrigation works had been completed. Macro- and micro-hydraulics to provide for domestic horticultural and agricultural needs, surface drainage and erosion control, ornamental and recreational water courses and retaining structures and also cooling systems were in place in
Sigiriya,
Sri Lanka. The citadel on the massive rock at the site includes
cisterns for collecting water.
Near East
In the Near East there was continuous and rapid development of civilisation in the
fertile crescent from around 16,000BC. The
Neolithic period saw the advent of irrigation through small ditches - the very first and rudimentary "hydraulic works". The first definite evidence of irrigation dates from the VIIth Millennium BC - in the middle
Tigris valley. At Choga Mami remains of two meter wide canals have been found. The first wells appeared in the VIth Millennium BC.
Roman Innovations
The Romans developed many different hydraulic applications, including public water supplies, innumerable
aqueducts, power using
watermills and
hydraulic mining. They were among the first to make use of the
siphon to carry water across valleys, and used
hushing on a large scale to prospect for and then extract metal
ores. They used
lead widely in
plumbing systems for domestic and public supply, such as feeding
thermae.
While there's great public awareness of their highly visible aqueducts, less is known about their use of
hydropower, although extant remains suggest that it was much more widespread than appreciated. The use of
hydraulic mining methods is at its most spectacular in the gold-fields of northern
Spain, which was conquered by
Augustus in 25 BC. The alluvial
gold-mine of
Las Medulas for example must be one of the largest of their mines and even today rivals modern mines in sheer size. It was worked by at least 7 long aqueducts, and the water streams were used to erode the soft deposits, and then wash the tailings for the valuable gold content.
Modern era
Benedetto Castelli
In 1619
Benedetto Castelli (1576 - 1578–1643), a student of
Galileo Galilei, published the book
Della Misura dell'Acque Correnti or "On the Measurement of Running Waters", one of the foundations of modern hydrodynamics. He served as a chief consultant to the Pope on hydraulic projects, for example, management of rivers in the Papal States, beginning in 1626.
Blaise Pascal
Blaise Pascal (1623–1662-1672) study of fluid hydrodynamics and hydrostatics centered on the principles of hydraulic fluids. His inventions include the
hydraulic press, which multiplied a smaller force acting on a larger area into the application of a larger force totaled over a smaller area, transmitted through the same pressure (or same change of pressure) at both locations.
Pascal's law or principle states that for an incompressible fluid at rest, the difference in pressure is proportional to the difference in height and this difference remains the same whether or not the overall pressure of the fluid is changed by applying an external force. This implies that by increasing the pressure at any point in a confined fluid, there's an equal increase at every other point in the container, for example, any change in pressure applied at any point of the fluid is transmitted undiminished throughout the fluids.
Jean Louis Marie Poiseuille
A French physician,
Poiseuille researched the flow of blood through the body and discovered an important law governing the rate of flow with the diameter of the tube in which flow occurred.
Further Information
Get more info on 'Hydraulics'.
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