This article discusses how besides its life-supporting and other essential applications, water has been combined with hydraulic systems for aesthetics, amusement, and relaxation since ancient times. Al-Jazari in Mesopotamia designed several ingenious fountains with moving objects in the late 12th century, improving upon the earlier works of the Banu Musa. Three brothers, the Banu Musa worked as engineers and scientists under the patronage of the caliphs of Baghdad in the ninth century. Today, many municipalities incorporate fountains to beautify their streets. Amusement parks and resorts invest millions of dollars to build fountains that create special effects to attract visitors. Home improvement centers and interior design firms market indoor fountains to provide a calming effect in our spaces. The advances made in computer-controlled devices allow impressive controls to be used in the fountain design and operation. Mechanical engineers can play an important role in the design of new fountains, especially in large-scale units, where knowledge of hydraulic systems and other skills come into play.
Water is one of the most precious natural materials. It is essential for sustaining life and for the operation and maintenance of industrial plants. Besides its life-supporting and other essential applications, water has been combined with hydraulic systems for aesthetics, amusement, and relaxation since ancient times.
Probably everyone has seen captivating water fountains in public buildings, amusement parks, or private houses. The purpose of a fountain can be to beautify the environment, to provide evaporative cooling, to create a special effect, to mask traffic noise, or to serve as an aid to relaxation.
History records that the rulers of ancient Egypt and Mesopotamia incorporated fountains in their palaces for decorative and evaporative cooling purposes. In the classical Greek and Roman cultures, highly developed fountains served as utilitarian and decorative objects. A surge of interest in sculptural fountains began during the Renaissance Today, elaborate sculptural fountains can be seen throughout Europe, as in the Trevi fountain in Italy.
Fountains with special effects were made by incorporating complex mechanical elements. For example, in the mid-16th century, a water organ was designed for Villa d'Este in Tivoli, near Rome. As people stepped on certain pavement blocks near the fountain, the pipes would be activated and the organ played.
The villa was a residence of cardinals, who entertained celebrated guests, including Franz Liszt. No one can say that the water organ was the direct cause, but in the late 1870s, Liszt composed a piece called "Les jeux d'eaux a la Villa d'Este," or "The Fountains at the Villa d'Este." The phrase "jeux d'eaux" can also be translated "games of waters."
That was not the first time fountain designers used mechanical devices for special effects. Hero of Alexandria, according to various writings, had several fountain designs that used floats, levers, and pulleys to move statues, and used compressed air to create a whistling sound. Hero wrote The Pneumatics, a treatise that included descriptions of siphons, valves, pumps, and a rudimentary steam engine in the middle of the first century.
Al-Jazari in Mesopotamia designed several ingenious fountains with moving objects in the late 12th century, improving upon the earlier works of the Banu Musa. Three brothers, the Banu Musa worked as engineers and scientists under the patronage of the caliphs of Baghdad in the ninth century. In The Book of Knowledge of Ingenious Mechanical Devices, Al-Jazari documented detailed construction steps for various objects, such as clocks and trick vessels.
In Islamic civilization, a pool with a fountain would be placed in the courtyard or garden, with radiating canals from the pool representing the rivers of paradise. The fountains at the Alhambra palace gardens in Spain and the formal gardens in Iran are examples of this tradition.
From the Simple to the Complex
Fountains appear in many different forms and complexities, from a simple round tube emitting a single jet of water to a multilevel arrangement of individual nozzles producing controlled spray patterns. In some fountains, air is allowed to mix with the water jet-for example, through an air induction tube-to produce white foam. Ornamental fountains incorporate special nozzles, with a deflector at the opening, that produce a sheet of water resembling various shapes, such as a mushroom or a tulip. Such nozzles are readily available from garden specialty stores.
The more recent use of computer-controlled devices has led to the design of innovative fountains with special effects. For example, in 1978, Koichi Kawamura and Yoshiko Kawamura patented a portable fountain display that consists of several slanting rows, with several nozzles in each row (U.S. patent No. 4,111,363). A basin is situated at the bottom to collect the water for circulation. The flow in each nozzle is individually controlled. Thus, by programming and activating an appropriate set of control valves, the resulting water jets can resemble symbols, letters, or the time of day.
Dave Ayer, Mark Fuller, and Lee Sim, seniors in the Department of Civil Engineering at the University of Utah in 1976, designed a fountain nozzle that produced a coherent and laminar stream of water. The water j et thus produced looks like a glass rod flying through the air. Similar fountains have been installed in several theme parks, including Epcot Center.
After working for six years with Walt Disney Imagineering, Fuller established his own company, WET Design, in Los Angeles, specializing in the creation of water features. The company has designed fountains for many locations in the United States and several cities around the world.
In 1992, Fuller and a co-inventor, Alan Robinson, mounted laminar flow nozzles on platforms whose angles, with respect to the ground, were individually controllable (U.S. patent No. 5,115,973). By oscillating the platforms, laminar streams move through the air in a beautiful arc-like manner. Such fountains can be seen at the West Edmonton Mall in Canada.
Another example of design is a fountain that shoots up individual large drops of water at predetermined time intervals. A fast-acting control valve is used to produce the drops. Arranging a series of these fountains, and activating them in a synchronized manner can produce mesmerizing three-dimensional patterns made of water droplets. An example of such a design, a product of WET Design, can be seen at King Fahd Airport in Saudi Arabia.
Fuller and Robinson invented an apparatus in 1987 that creates kinetic water displays (U.S. patent No. 4,715,136). It consists of a horizontal chamber with an arrangement of grid-like holes on its upper surface. As the water jets flow out, they impinge upon a transparent plate above, and parallel to, the perforated surface of the chamber. The interaction among the impinging jets creates a visually pleasing display. The entire water display can be installed in the ground with the transparent plate flush with a pavement surface-for example, at the entrance to a building.
WET Design also created the sophisticated and elaborate fountains at the Bellagio hotel, operated by MGM Grand Inc. in Las Vegas. About 1,200 nozzles are installed in a man-made lake with a volume of 27 million gallons. Compressed air is used to push out large masses of water that reach heights of240 feet. The water jets are enhanced by 4,500 underwater lights and 230 gallons per minute of fog, and are accompanied by music. As much as 17,000 gallons of water can be in the air at any one time. A show lasts about five minutes and uses 25,000 cubic feet of compressed air to drive the water jets. The total load is 7.5 megawatts and 350 miles of electrical wire are used.
Using Motor Control Technology
Some of the nozzles can pivot through precise maneuvers via motor control technology, causing a dazzling curving flow of water. As a result, the water jets are made to literally dance as the music is played. The sequences of water jets and rotation of nozzles are controlled by computers to coordinate with specific pieces of music. The technologies of compressed air and pivoting nozzles have been patented by WET Design.
The company has video of the fountains in action at its Web site, www.wetdesign.com/client/bellagio/index.html.
A basic and general fountain loop consists of a pump, piping, regulating valve, nozzle, filter, and basin. Many types of pumps are used. There are dry centrifugal pumps ranging from 0.25 to 100 horsepower and submersibles from as little as 0.05 hp.
Five Miles of Pipes
The piping could be a length of plastic tubing and a flow regulator to feed a single nozzle in a small fountain, or a network of pipes with programmable controls and regulators to feed several nozzles in large fountains. The fountains of Bellagio in Las Vegas have about five miles of pipes. In some fountains, gas pipes are also included to supply fuel for fireworks, which add another display feature.
The filter, in general, removes particulate and foreign matter from the water. It may also add chemicals to prevent the growth of algae and other undesirable organisms. The basin's depth and area are of importance so that the fountain spray is contained, and a great enough volume of water is held for proper operation of the pump.
The manufacturer rates commercially available fountain nozzles by capacity (usually gallons per minute) and by the pressure required at the nozzle head. Based on these facts, the piping can be sized so that the water is delivered at the nozzle within a prescribed velocity.
Given the capacity requirement and the selected pipe size, an engineer can calculate the head loss of the loop and select a proper pump. If the nozzle is fabricated in-house, then its pressure loss must be determined experimentally prior to the loss calculation for the fountain loop.
Many municipalities incorporate fountains to beautify their streets. Amusement parks and resorts invest millions of dollars to build fountains that create special effects to attract visitors. Home improvement centers and interior design firms market indoor fountains to provide a calming effect in our spaces. The advances made in computer- controlled devices allow impressive controls to be used in the fountain design and operation.
Mechanical engineers can play an important role in the design of new fountains, especially in large-scale units, where knowledge of hydraulic systems and other skills come into play. What's more, engineering educators could devise innovative projects for students and take advantage of the inherent multidisciplinary nature of fountain design, combining engineering and art.