Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries.
Microfluidics refers to the behaviour, precise control, and manipulation of fluids that are geometrically constrained to a small scale at which capillary penetration governs mass transport. It is a multidisciplinary field that involves engineering, physics, chemistry, biochemistry, nanotechnology, and biotechnology. It has practical applications in the design of systems that process low volumes of fluids to achieve multiplexing, automation, and high-throughput screening. Microfluidics emerged in the beginning of the 1980s and is used in the development of inkjet printheads, DNA chips, lab-on-a-chip technology, micro-propulsion, and micro-thermal technologies.
A whistle is an instrument which produces sound from a stream of gas, most commonly air. It may be mouth-operated, or powered by air pressure, steam, or other means. Whistles vary in size from a small slide whistle or nose flute type to a large multi-piped church organ.
In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after Daniel Bernoulli who published it in his book Hydrodynamica in 1738. Although Bernoulli deduced that pressure decreases when the flow speed increases, it was Leonhard Euler who derived Bernoulli's equation in its usual form in 1752. The principle is only applicable for isentropic flows: when the effects of irreversible processes and non-adiabatic processes are small and can be neglected.
"I'm a Little Teapot" is an American song describing the heating and pouring of a teapot or a whistling tea kettle. The song was originally written by George Harold Sanders and Clarence Z. Kelley and published in 1939. By 1941, a Newsweek article referred to the song as "the next inane novelty song to sweep the country".
Sir Michael James Lighthill, was a British applied mathematician, known for his pioneering work in the field of aeroacoustics.
A kettle, sometimes called a tea kettle or teakettle, is a type of pot, specialized for boiling water, with a lid, spout, and handle, or a small kitchen appliance of similar shape that functions in a self-contained manner. Kettles can be heated either by placing on a stove, or by their own internal electric heating element in the appliance versions.
The vortex tube, also known as the Ranque-Hilsch vortex tube, is a mechanical device that separates a compressed gas into hot and cold streams. The gas emerging from the "hot" end can reach temperatures of 200 °C, and the gas emerging from the "cold end" can reach −50 °C (−58 °F). It has no moving parts.
A bubble ring, or toroidal bubble, is an underwater vortex ring where an air bubble occupies the core of the vortex, forming a ring shape. The ring of air as well as the nearby water spins poloidally as it travels through the water, much like a flexible bracelet might spin when it is rolled on to a person's arm. The faster the bubble ring spins, the more stable it becomes. Bubble rings and smoke rings are both examples of vortex rings—the physics of which is still under active study in fluid dynamics. Devices have been invented which generate bubble vortex rings.
David George Crighton, FRS was a British mathematician and physicist.
A steam whistle is a device used to produce sound with the aid of live steam, which acts as a vibrating system.
Aeroacoustics is a branch of acoustics that studies noise generation via either turbulent fluid motion or aerodynamic forces interacting with surfaces. Noise generation can also be associated with periodically varying flows. A notable example of this phenomenon is the Aeolian tones produced by wind blowing over fixed objects.
Harry L. Swinney is an American physicist noted for his contributions to the field of nonlinear dynamics.
John "Shôn" Eirwyn Ffowcs Williams, is Emeritus Rank Professor of Engineering at the University of Cambridge and a former Master of Emmanuel College, Cambridge (1996–2002). He may be best known for his contributions to Aeroacoustics, in particular for his work on Concorde. Together with one of his students, David Hawkings, he introduced the far-field integration method in computational aeroacoustics based on Lighthill's acoustic analogy, known as the Ffowcs Williams-Hawkings analogy.
The tea leaf paradox is a phenomenon where tea leaves in a cup of tea migrate to the center and bottom of the cup after being stirred rather than being forced to the edges of the cup, as would be expected in a spiral centrifuge. The correct physical explanation of the paradox was for the first time given by James Thomson in 1857. He correctly connected the appearance of secondary flow with ″friction on the bottom″. The formation of secondary flows in an annular channel was theoretically treated by Boussinesq as early as in 1868. The migration of near-bottom particles in river-bend flows was experimentally investigated by A. Ya. Milovich in 1913. The solution first came from Albert Einstein in a 1926 paper in which he explained the erosion of river banks, and repudiated Baer's law.
Mohammed Yousuff Hussaini is an Indian born American applied mathematician. He is the Sir James Lighthill Professor of Mathematics and Computational Science & Engineering at the Florida State University, United States. Hussaini is also the holder of the TMC Eminent Scholar Chair in High Performance Computing at FSU. He is widely known for his research in scientific computation, particularly in the field of computational fluid dynamics (CFD) and Control and optimization. Hussaini co-authored the popular book Spectral Methods in Fluid Dynamics with Claudio Canuto, Alfio Quarteroni, and Thomas Zang. He is the editor-in-chief of the journal Theoretical and Computational Fluid Dynamics.
Multiscale turbulence is a class of turbulent flows in which the chaotic motion of the fluid is forced at different length and/or time scales. This is usually achieved by immersing in a moving fluid a body with a multiscale, often fractal-like, arrangement of length scales. This arrangement of scales can be either passive or active
Raymond Ethan Goldstein FRS FInstP is Schlumberger Professor of Complex Physical Systems in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge and a Fellow of Churchill College, Cambridge.
A whistle is a device that makes sound from blowing air. The physical theory of the sound-making process is an example of the application of the science of fluid dynamics. Knowledge of the geometry, dimensions and fluid properties can allow prediction of the properties of the whistle. The principles relevant to whistle operation also have applications in other areas such as fluid flow measurement.
Ravindra Nath Sudan was an Indian-American electrical engineer and physicist who specialized in plasma physics. He was known for independently discovering the whistler instability in 1963, an instability which causes audible low-frequency radio waves to be emitted in the magnetosphere in the form of whistler waves. He also pioneered the study of the generation and propagation of intense ion beams, and contributed to theories of plasma instabilities and plasma turbulence.
