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Paul Richard Heinrich Blasius
Paul Richard Heinrich Blasius (9 August 1883 – 24 April 1970) was a German fluid dynamics physicist. He was one of the first students of Prandtl Ludwig Prandtl (4 February 1875 – 15 August 1953) was a German Fluid mechanics, fluid dynamicist, physicist and aerospace scientist. He was a pioneer in the development of rigorous systematic mathematical analyses which he used for underlyin .... Blasius provided a mathematical basis for boundary-layer drag but also showed as early as 1911 that the resistance to flow through smooth pipes could be expressed in terms of the Reynolds number for both laminar and turbulent flow. After six years in science he changed to ''Ingenieurschule Hamburg'' (today: University of Applied Sciences Hamburg) and became a Professor. On 1 April 1962 Heinrich Blasius celebrated his 50th anniversary in teaching. He was active in his field until he died on 24 April 1970. One of his most notable contributions involves a description of the steady two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population within city limits, highest population within its city limits of any city in the European Union. The city is also one of the states of Germany, being the List of German states by area, third smallest state in the country by area. Berlin is surrounded by the state of Brandenburg, and Brandenburg's capital Potsdam is nearby. The urban area of Berlin has a population of over 4.6 million and is therefore the most populous urban area in Germany. The Berlin/Brandenburg Metropolitan Region, Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's second-largest metropolitan region after the Rhine-Ruhr region, as well as the List of EU metropolitan areas by GDP, fifth-biggest metropolitan region by GDP in the European Union. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germans
Germans (, ) are the natives or inhabitants of Germany, or sometimes more broadly any people who are of German descent or native speakers of the German language. The Basic Law for the Federal Republic of Germany, constitution of Germany, implemented in 1949 following the end of World War II, defines a German as a German nationality law, German citizen. During the 19th and much of the 20th century, discussions on German identity were dominated by concepts of a common language, culture, descent, and history.. "German identity developed through a long historical process that led, in the late 19th and early 20th centuries, to the definition of the German nation as both a community of descent (Volksgemeinschaft) and shared culture and experience. Today, the German language is the primary though not exclusive criterion of German identity." Today, the German language is widely seen as the primary, though not exclusive, criterion of German identity. Estimates on the total number of Germ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1970 Deaths
Events January * January 1 – Unix time epoch reached at 00:00:00 UTC. * January 5 – The 7.1 1970 Tonghai earthquake, Tonghai earthquake shakes Tonghai County, Yunnan province, China, with a maximum Mercalli intensity scale, Mercalli intensity of X (''Extreme''). Between 10,000 and 14,621 are killed and 30,000 injured. * January 15 – After a 32-month fight for independence from Nigeria, Biafran forces under Philip Effiong formally surrender to General Yakubu Gowon, ending the Nigerian Civil War. February * February 1 – The Benavídez rail disaster near Buenos Aires, Argentina (a rear-end collision) kills 236. * February 10 – An avalanche at Val-d'Isère, France, kills 41 tourists. * February 11 – ''Ohsumi (satellite), Ohsumi'', Japan's first satellite, is launched on a Lambda-4 rocket. * February 22 – Guyana becomes a Republic within the Commonwealth of Nations. * February – Multi-business Conglomerate (company), conglomerate Virgin Group is founded as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1883 Births
Events January * January 4 – ''Life (magazine), Life'' magazine is founded in Los Angeles, California, United States. * January 10 – A Newhall House Hotel Fire, fire at the Newhall Hotel in Milwaukee, Wisconsin, United States, kills 73 people. * January 16 – The Pendleton Civil Service Reform Act, establishing the United States civil service, is passed. * January 19 – The first electric lighting system employing overhead wires begins service in Roselle, New Jersey, United States, installed by Thomas Edison. February * February 15 – Tokyo Electrical Lightning Grid, predecessor of Tokyo Electrical Power (TEPCO), one of the largest electrical grids in Asia and the world, is founded in Japan. * February 16 – The ''Ladies' Home Journal'' is published for the first time, in the United States. * February 23 – Alabama becomes the first U.S. state to enact an Competition law, antitrust law. * February 28 – The first vaudeville th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willi H
Willi is a given name, nickname (often a short form or hypocorism of Wilhelm) and surname. Notable people with the name include: Given name * Willi Apel (1893–1988), German-American musicologist * Willi Boskovsky (1909–1991), Austrian violinist and conductor * Willi Forst (1903–1980), born Wilhelm Anton Frohs, Austrian actor, screenwriter, film director, film producer and singer * Willi Hennig (1913–1976), German biologist * Willi Liebherr (born 1947), German-Swiss businessman and billionaire * Willi Smith (1948–1987), African-American fashion designer * Willi Tiefel, German footballer * Willi Ziegler (1929–2002), German paleontologist Nickname * Willi Graf (1918–1943), member of the White Rose anti-Nazi resistance group under consideration for sainthood * Willi Münzenberg (1889–1940), German communist political activist and publisher * Willi Orbán (born 1992), German-Hungarian footballer * Willi Ostermann (1876–1936), German lyricist, composer and singer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blasius Function
In physics and fluid mechanics, a Blasius boundary layer (named after Paul Richard Heinrich Blasius) describes the steady two-dimensional laminar boundary layer that forms on a semi-infinite plate which is held parallel to a constant unidirectional flow. Falkner and Skan later generalized Blasius' solution to wedge flow ( Falkner–Skan boundary layer), i.e. flows in which the plate is not parallel to the flow. Prandtl's boundary layer equations Using scaling arguments, Ludwig Prandtl argued that about half of the terms in the Navier-Stokes equations are negligible in boundary layer flows (except in a small region near the leading edge of the plate). This leads to a reduced set of equations known as the boundary layer equations. For steady incompressible flow with constant viscosity and density, these read: * Mass Continuity: \dfrac + \dfrac = 0 * x-Momentum: u \dfrac + v \dfrac = - \dfrac \dfrac + \dfrac * y-Momentum: 0 = - \dfrac Here the coordinate system is chose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fanning Friction Factor
The Fanning friction factor (named after American engineer John T. Fanning) is a dimensionless number used as a local parameter in continuum mechanics calculations. It is defined as the ratio between the local shear stress and the local flow kinetic energy density: f = \frac where : is the local Fanning friction factor (dimensionless); : is the local shear stress (units of pascals (Pa) = kg/m, or pounds per square foot (psf) = lbm/ft); : is the bulk dynamic pressure (Pa or psf), given by: q = \frac \rho u^2 :: is the density of the fluid ( kg/m or lbm/ft) :: is the bulk flow velocity (m/s or ft/s) In particular the shear stress at the wall can, in turn, be related to the pressure loss by multiplying the wall shear stress by the wall area ( 2 \pi R L for a pipe with circular cross section) and dividing by the cross-sectional flow area ( \pi R^2 for a pipe with circular cross section). Thus \Delta P = f \frac q = f \frac \rho u^2 Fanning friction factor formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-infinite
In mathematics, semi-infinite objects are objects which are infinite or unbounded in some but not all possible ways. In ordered structures and Euclidean spaces Generally, a semi-infinite set is bounded in one direction, and unbounded in another. For instance, the natural numbers are semi-infinite considered as a subset of the integers; similarly, the intervals (c,\infty) and (-\infty,c) and their closed counterparts are semi-infinite subsets of \R if c is finite. Half-spaces and half-lines are sometimes described as semi-infinite regions. Semi-infinite regions occur frequently in the study of differential equations. For instance, one might study solutions of the heat equation in an idealised semi-infinite metal bar. A semi-infinite integral is an improper integral over a semi-infinite interval. More generally, objects indexed or parametrised by semi-infinite sets may be described as semi-infinite. Most forms of semi-infiniteness are boundedness properties, not cardinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reynolds Number
In fluid dynamics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between Inertia, inertial and viscous forces. At low Reynolds numbers, flows tend to be dominated by laminar flow, laminar (sheet-like) flow, while at high Reynolds numbers, flows tend to be turbulence, turbulent. The turbulence results from differences in the fluid's speed and direction, which may sometimes intersect or even move counter to the overall direction of the flow (Eddy (fluid dynamics), eddy currents). These eddy currents begin to churn the flow, using up energy in the process, which for liquids increases the chances of cavitation. The Reynolds number has wide applications, ranging from liquid flow in a pipe to the passage of air over an aircraft wing. It is used to predict the transition from laminar–turbulent transition, laminar to turbulent flow and is used in the scaling of similar but different-sized fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boundary-layer
In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condition (zero velocity at the wall). The flow velocity then monotonically increases above the surface until it returns to the bulk flow velocity. The thin layer consisting of fluid whose velocity has not yet returned to the bulk flow velocity is called the velocity boundary layer. The air next to a human is heated, resulting in gravity-induced convective airflow, which results in both a velocity and thermal boundary layer. A breeze disrupts the boundary layer, and hair and clothing protect it, making the human feel cooler or warmer. On an aircraft wing, the velocity boundary layer is the part of the flow close to the wing, where viscous forces distort the surrounding non-viscous flow. In the Earth's atmosphere, the atmospheric boundary laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion) and (the study of water and other liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moment (physics), moments on aircraft, determining the mass flow rate of petroleum through pipeline transport, pipelines, weather forecasting, predicting weather patterns, understanding nebulae in interstellar space, understanding large scale Geophysical fluid dynamics, geophysical flows involving oceans/atmosphere and Nuclear weapon design, modelling fission weapon detonation. Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
