Paul Richard Heinrich Blasius (9 August 1883 – 24 April 1970) was a
German
German(s) may refer to:
* Germany (of or related to)
** Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ge ...
fluid dynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) an ...
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 caus ...
. He was one of the first students of
Prandtl
Ludwig Prandtl (4 February 1875 – 15 August 1953) 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 ...
.
Blasius provided a mathematical basis for
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 condi ...
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
In fluid mechanics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situations by measuring the ratio between inertial and viscous forces. At low Reynolds numbers, flows tend to be domi ...
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-dimensional
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 condi ...
that forms on a
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 ...
plate that is held parallel to a constant unidirectional flow
.
Correlations
First law of Blasius for turbulent
Fanning friction factor
The Fanning friction factor, named after John Thomas 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 d ...
:
:
Second law of Blasius for turbulent
Fanning friction factor
The Fanning friction factor, named after John Thomas 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 d ...
:
:
Law of Blasius for friction coefficient in turbulent pipe flow:
:
See also
*
Blasius function
Notes
References
*
Hager, W.H., "Blasius: A life in research and education," ''Experiments in Fluids,'' 34: 566–571 (2003)
* Blasius, H., "Das Aehnlichkeitsgesetz bei Reibungsvorgängen in Flüssigkeiten", Mitteilungen über Forschungsarbeiten auf dem Gebiete des Ingenieurwesens, vol.134, VDI-Verlag Berlin (1913)
External links
*
{{DEFAULTSORT:Blasius, Heinrich
1883 births
1970 deaths
20th-century German physicists
Fluid dynamicists