Cavitation in fluid mechanics and engineering normally refers to the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal, causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial cavitation and non-inertial cavitation.
A propeller is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft with an approximately horizontal axis.
A turbopump is a propellant pump with two main components: a rotodynamic pump and a driving gas turbine, usually both mounted on the same shaft, or sometimes geared together. They were initially developed in Germany in the early 1940s. The purpose of a turbopump is to produce a high-pressure fluid for feeding a combustion chamber or other use. While other use cases exist, they are most commonly found in liquid rocket engines.
Supercavitation is the use of a cavitation bubble to reduce skin friction drag on a submerged object and enable high speeds. Applications include torpedoes and propellers, but in theory, the technique could be extended to an entire underwater vessel.
A ship model basin is a basin or tank used to carry out hydrodynamic tests with ship models, for the purpose of designing a new ship, or refining the design of a ship to improve the ship's performance at sea. It can also refer to the organization that owns and operates such a facility.
Ludwig Prandtl was a German fluid dynamicist, physicist and aerospace scientist. He was a pioneer in the development of rigorous systematic mathematical analyses which he used for underlying the science of aerodynamics, which have come to form the basis of the applied science of aeronautical engineering. In the 1920s, he developed the mathematical basis for the fundamental principles of subsonic aerodynamics in particular; and in general up to and including transonic velocities. His studies identified the boundary layer, thin-airfoils, and lifting-line theories. The Prandtl number was named after him.
National Taiwan Ocean University is a national university in Zhongzheng District, Keelung, Taiwan. NTOU is a member of University System of Taipei.
An impeller, or impellor, is a driven rotor used to increase the pressure and flow of a fluid. It is the opposite of a turbine, which extracts energy from, and reduces the pressure of, a flowing fluid.
The Carderock Division of the Naval Surface Warfare Center is one of eight Naval Sea Systems Command (NAVSEA) Surface Warfare Centers. The headquarters, located in Carderock, Maryland, includes the historic David Taylor Model Basin. The division includes remote sites across the United States concentrating on engineering, testing and modelling ship and ship's systems for the Navy. It has about 3,200 scientists, engineers, and support personnel working in more than 40 disciplines from fundamental science to applied and in-service engineering.
Marine engineering is the engineering of boats, ships, submarines, and any other marine vessel. Here it is also taken to include the engineering of other ocean systems and structures – referred to in certain academic and professional circles as "ocean engineering". After completing this degree one can join a ship as an officer in engine department and eventually rise to the rank of a chief engineer. This rank is one of the top ranks onboard and is equal to the rank of a ship's captain. Marine engineering is the highly preferred course to join merchant Navy as an officer as it provides ample opportunities in terms of both onboard and onshore jobs.
Albert Betz was a German physicist and a pioneer of wind turbine technology.
MARIN, the Maritime Research Institute Netherlands, is the leading institute in the world for hydrodynamic research and maritime technology. The services incorporate a unique combination of simulation, model testing, full-scale measurements and training programmes. MARIN provides services to the shipbuilding and offshore industry and governments. Customers include commercial ship builders, fleet owners, naval architects, classification societies, oil and LNG companies and navies all over the world.
William B. Morgan is an American naval architect and renowned expert in propeller design.
The Emerson Cavitation Tunnel is a propeller testing facility that is part of the School of Engineering at Newcastle University.
The Saint Anthony Falls Laboratory, or SAFL, is a research laboratory situated on Hennepin Island in the Mississippi River in Minneapolis, Minnesota, United States. Its primary research is in "Engineering, Environmental, Biological, and Geophysical Fluid Mechanics". It is affiliated with the University of Minnesota's College of Science and Engineering. Research is conducted by graduate students and faculty alike using the 16,000 square feet of research space and 24 different specialized facilities.
The National Penghu University of Science and Technology is a public university located in Magong City, Penghu, Taiwan. It is one of the few higher education institutions located outside of Taiwan Island.
National Dong Hwa University (NDHU) is a national research university located in Hualien, Taiwan. Established in 1994, NDHU is widely ranked as Top 10% university in Taiwan by THE, QS, U.S. News, which offers sixth widest range of disciplines in Taiwan, including the sciences, engineering, computer science, environmental studies, oceanography, law, arts, design, humanities, anthropology, social sciences, education sciences, music, and business.
The Garfield Thomas Water Tunnel is one of the U.S. Navy's principal experimental hydrodynamic research facilities and is operated by the Penn State Applied Research Laboratory. The facility was completed and entered operation in 1949. The facility is named after Lieutenant W. Garfield Thomas Jr., a Penn State journalism graduate who was killed in World War II. For a long time, the Garfield Thomas Water Tunnel was the largest circulating water tunnel in the world. It has been declared a historic mechanical engineering landmark by the American Society of Mechanical Engineers.
Joseph Katz is an Israel-born American fluid dynamicist, known for his work on experimental fluid mechanics, cavitation phenomena and multiphase flow, turbulence, turbomachinery flows and oceanography flows, flow-induced vibrations and noise, and development of optical flow diagnostics techniques, including Particle Image Velocimetry (PIV) and Holographic Particle Image Velocimetry (HPIV). As of 2005, he is the William F. Ward Sr. Distinguished Professor at the Department of Mechanical Engineering of the Whiting School of Engineering at the Johns Hopkins University.
NDHU Department of Computer Science and Information Engineering is a research-intensive school of Computer Science within NDHU College of Science and Engineering and widely regarded as top 5 academic department of computer science in Taiwan. NDHU CSIE has Taiwan's largest percentage of international students, with more than one-third coming from countries outside of Taiwan.
