One of the first engineering problems humankind faced as cities were developed
was the supply of water for domestic use and irrigation of crops. Our
urban lifestyles can be retained only with abundant water, and it is clear
from archeology that every successful civilization of prehistory invested in
the construction and maintenance of water systems. The Roman aqueducts,
some of which are still in use, are the best known examples. However, perhaps
the most impressive engineering from a technical viewpoint was done
at the Hellenistic city of Pergamon in present-day Turkey. There, from 283
to 133 BC, they built a series of pressurized lead and clay pipelines (Fig.
1–11), up to 45 km long that operated at pressures exceeding 1.7 MPa (180
m of head). Unfortunately, the names of almost all these early builders are
During the Middle Ages the application of fluid machinery slowly but
steadily expanded. Elegant piston pumps were developed for dewatering
mines, and the watermill and windmill were perfected to grind grain, forge
metal, and for other tasks. For the first time in recorded human history significant
work was being done without the power of a muscle supplied by a
person or animal, and these inventions are generally credited with enabling
the later industrial revolution. Again the creators of most of the progress are
unknown, but the devices themselves were well documented by several
technical writers such as Georgius Agricola (Fig. 1–12).
The Renaissance brought continued development of fluid systems and
machines, but more importantly, the scientific method was perfected and
adopted throughout Europe. Simon Stevin (1548–1617), Galileo Galilei
(1564–1642), Edme Mariotte (1620–1684), and Evangelista Torricelli
(1608–1647) were among the first to apply the method to fluids as they
investigated hydrostatic pressure distributions and vacuums. That work was
integrated and refined by the brilliant mathematician, Blaise Pascal (1623–
1662). The Italian monk, Benedetto Castelli (1577–1644) was the first person
to publish a statement of the continuity principle for fluids. Besides formulating
his equations of motion for solids, Sir Isaac Newton (1643–1727)
applied his laws to fluids and explored fluid inertia and resistance, free jets,
and viscosity. That effort was built upon by the Swiss Daniel Bernoulli
(1700–1782) and his associate Leonard Euler (1707–1783). Together, their
work defined the energy and momentum equations. Bernoulli’s 1738 classic
treatise Hydrodynamica may be considered the first fluid mechanics text.
Finally, Jean d’Alembert (1717–1789) developed the idea of velocity and
acceleration components, a differential expression of continuity, and his
“paradox” of zero resistance to steady uniform motion.
The development of fluid mechanics theory up through the end of the
eighteenth century had little impact on engineering since fluid properties
and parameters were poorly quantified, and most theories were abstractions
that could not be quantified for design purposes. That was to change with
the development of the French school of engineering led by Riche de Prony
(1755–1839). Prony (still known for his brake to measure power) and his
associates in Paris at the Ecole Polytechnic and the Ecole Ponts et Chaussees
were the first to integrate calculus and scientific theory into the engineering
curriculum, which became the model for the rest of the world. (So now
you know whom to blame for your painful freshman year.) Antonie Chezy
(1718–1798), Louis Navier (1785–1836), Gaspard Coriolis (1792–1843),
Henry Darcy (1803–1858), and many other contributors to fluid engineering
and theory were students and/or instructors at the schools.
By the mid nineteenth century fundamental advances were coming on
several fronts. The physician Jean Poiseuille (1799–1869) had accurately
measured flow in capillary tubes for multiple fluids, while in Germany
Gotthilf Hagen (1797–1884) had differentiated between laminar and turbulent
flow in pipes. In England, Lord Osborn Reynolds (1842–1912) continued
that work and developed the dimensionless number that bears his name.
Similarly, in parallel to the early work of Navier, George Stokes (1819–
1903) completed the general equations of fluid motion with friction that
take their names. William Froude (1810–1879) almost single-handedly
developed the procedures and proved the value of physical model testing.
American expertise had become equal to the Europeans as demonstrated by
James Francis’s (1815–1892) and Lester Pelton’s (1829–1908) pioneering
work in turbines and Clemens Herschel’s (1842–1930) invention of the Venturi
meter.
The late nineteenth century was notable for the expansion of fluid theory
by Irish and English scientists and engineers, including in addition to
Reynolds and Stokes, William Thomson, Lord Kelvin (1824–1907), William
Strutt, Lord Rayleigh (1842–1919), and Sir Horace Lamb (1849–1934).
These individuals investigated a large number of problems including dimensional
analysis, irrotational flow, vortex motion, cavitation, and waves. In a
broader sense their work also explored the links between fluid mechanics,
thermodynamics, and heat transfer.
The dawn of the twentieth century brought two monumental developments.
First in 1903, the self-taught Wright brothers (Wilbur, 1867–1912;
Orville, 1871–1948) through application of theory and determined experimentation
perfected the airplane. Their primitive invention was complete
and contained all the major aspects of modern craft (Fig. 1–13). The
Navier–Stokes equations were of little use up to this time because they were
too difficult to solve. In a pioneering paper in 1904, the German Ludwig
Prandtl (1875–1953) showed that fluid flows can be divided into a layer
near the walls, the boundary layer, where the friction effects are significant
and an outer layer where such effects are negligible and the simplified Euler