The science of fluid mechanics is neither new nor biblical; however, most of the progress in this field was made in the 20th century. Therefore it is appropriate to open this text with a brief history of the discipline, with only a very few names mentioned.
As far as we can document history, fluid dynamics and related engineering were always integral parts of human evolution. Ancient civilizations built ships, sails, irrigation systems, and flood-management structures, all requiring some basic understanding of fluid flow. Perhaps the best known early scientist in this field is Archimedes of Syracuse (287–212 b.c.e.), founder of the field now we call “fluid statics,” whose laws on buoyancy and flotation are used to this day.
A major leap in understanding fluid mechanics began with the European Renaissance of the 14th–17th centuries. The famous Italian painter–sculptor, Leonardo da Vinci (1452–1519), was one of the first to document basic laws such as the conservation of mass. He sketched complex flow fields, suggested feasible configurations for airplanes, parachutes, and even helicopters, and introduced the principle of streamlining to reduce drag. During the next couple of hundred years, the sciences were gradually developed and then suddenly accelerated by the rational mathematical approach of an Englishman, Sir Isaac Newton (1642–1727), to physics. Apart from the basic laws of mechanics, and particularly the second law connecting acceleration with force, the concepts for drag and shear in a moving fluid were developed by Newton, and his principles are widely used today.
The foundations of fluid mechanics really crystallized in the 18th century. One of the more famous scientists, Daniel Bernoulli (1700–1782, Dutch-Swiss), point...
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...e following subsections, only a few, which are used in introductory fluid mechanics, are mentioned.
Density
Density, by definition, is mass per unit volume. In the case of fluids, we can define the density (with the aid of Fig. 1.3) as the limit of this ratio when a measuring volume V shrinks to zero. We need to use this definition because density can change from one point to the other. Also in this picture, we can relate to a volume element in space that we can call “control volume,” which moves with the fluid or can be stationary (in any case it is better to place this control volume in inertial frames of reference).
Therefore the definition of density at a point is ρ = lim
V→0
_m
V
_
Typical units are kilograms per cubic meter (kg/m3) or grams per cubic centimeter (g/cm3). m V
Control volume
Figure 1.3. Mass m in a control volume V. Density is the ratio of
m/V.
They just forgot to mention the other effects of fluids in nature. “The influence of the fluid on a body moving through it depends not only on the body’s velocity but also on the velocity of the fluid,” this is called relative velocity ( ). The relative velocity of a body in a fluid has an effect on the magnitude of the acting forces. For example, as a long distance runner is running into a head wind, the force of the fluid is very strong. If the runner is running with the help of a tail wind, the current’s force is reduced and may even be unnoticeable.
Have you wondered why airplanes were ever able to fly or how racecars are able to stay on the ground at high speeds? They all use a scientific concept called Bernoulli’s principle, or more commonly known as Bernoulli’s equation. His principle simply states that the faster a fluid flows, the less pressure it applies, the slower the fluid flows, the more pressure it applies.
Bernoulli’s principle is the concept that as the speed of a moving fluid (liquid or gas) increases, the pressure within that fluid decreases. This principle was originally formulated in 1738 by the Swiss mathematician and physicist Daniel Bernoulli, it states that the total energy in a steadily flowing ...
Introduction to Aerodynamics Aerodynamics is the study of the motion of fluids in the gas state and bodies in motion relative to the fluid/air. In other words, the study of aerodynamics is the study of fluid dynamics specifically relating to air or the gas state of matter. When an object travels through fluid/air there are two types of flow characteristics that happen, laminar and turbulent. Laminar flow is a smooth, steady flow over a smooth surface and it has little disturbance. Intuition would lead to the belief that this type of air flow would be desirable.
Hepel explains the process of explaining atmospheric pressure by starting from the beginning with Galileo’s interest in the limitations of a simple suction pump. Galileo’s observation was that a simple suction pump, which draws water form a well by means of a piston that can be raised in the pump barrel, will lift water no higher than about 34 feet above the surface of the well. After Galileo’s death, his pupil Torricelli pursued this dilemma. Torricelli argued that the earth is surrounded by a sea of air that exerts pressure on the surface below, and that this pressure upon the surface of the well forces water up the pump barrel when the piston is raised. The maximum length of 34 feet for the water column in the barrel thus reflects simply the total pressure of the atmosphere upon the surface o...
Archimedes discovered many theorems in mechanics. His most famous one was named after him, ‘Archimedes’ Principle’, it gives the weight of a body immersed in a liquid. Archimedes, in this theorem stated that ‘any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the
This is a great discovery of Bernoulli. It seems to make sense when we apply it to blood vessels. Where the blood moves faster, the more it pushes forward, the less it pushes on the walls. A later more ingenious application for this idea is flying. The airplane was invented after Bernoulli but not due to him. The airplane and Bernoulli’s equation
Density is how much mass is in a certain volume. You can calculate density by dividing mass by volume. Water's density depends on its temperature and salinity. Cold water with a high salinity is more dense than warm water with a low salinity.
The invention of calculus started in the second half of the 17th Century. The few preceding centuries, known as the Renaissance period, marked a time of prosperity in different areas throughout Europe. Different philosophies emerged which resulted in a new form of mindset. Science and art were still very much interconnected and intermingled at this time, as exemplified by the work of artists and scientists such as Leonardo da Vinci. It is no surprise that revolutionary work in science and
Renaissance theory of the open system where a flow occurs both in and out. A Midsummer
On a more scientific note I am interested in mechanics of fluids. This interest was enforced last year when I had the opportunity to attend a lecture on fluid mechanics at P&G. At the conference I greatly expanded my knowledge regarding the physical aspect of fluids and their properties. In last year's AS course we have met a topic in this field. I will be applying ideas and knowledge gathered from last year for this investigation.
My purpose in applying to Newcastle University for graduate studies is to prepare myself for a career in research and development in the field of Fluid Dynamics. I am keen to pursue Ph.D. under the supervision of Professor Srinil in fluid dynamics as my primary area of interest. My motivation for graduate studies comes from the desire to be at the forefront of the pioneering developments in the field of fluid mechanics. I am confident that I possess the technical capabilities necessary to succeed in Newcastle University core requirement of the Ph.D. degree.
Sir Isaac Newton is the man well known for his discoveries around the term, Motion. He came up with three basic ideas, called Newton’s three laws of motion.
Since the days of Newton, the ideas of classical mechanics prevailed in the scientific community. The ideas of absolute velocity and absolute time were accepted phenomenon and were not at all challenged. However, as the nineteenth century drew to a close, new observations were being made, observations which contradicted the current theory of the time.
Projectile motion is used in our daily lives, from war, to the path of the water in the water fountain, to sports. When using a water fountain or hose, projectile motion can be used to describe the path and motion of the water. This technology was created by finding the angle at which the water would come out at a maximum height and the person using it would be able to drink it without leaning over too much. These types of projectile motion will be further explored and analyzed in this assessment.