Paul Richard Heinrich Blasius
Encyclopedia
Paul Richard Heinrich Blasius (1883 – 1970) was a German
fluid dynamics
engineer
.
He was one of the first students of Prandtl who 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.
One of his most notable contributions involves a description of the steady two-dimensional boundary-layer
that forms on a semi-infinite
plate that is held parallel to a constant unidirectional flow
.
around a fixed body enclosed by a contour 
, the net force on the body due to fluid motion is given by
where
is the constant fluid density. This is a contour integral which may be computed by using Cauchy's residue theorem
.
Second law of Blasius for turbulent fanning friction factor:
Law of Blasius for friction coefficient in turbulent pipe flow:
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
fluid dynamics
Fluid dynamics
In physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
.
He was one of the first students of Prandtl who 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.
One of his most notable contributions involves a description of the steady two-dimensional boundary-layer
Blasius boundary layer
In physics and fluid mechanics, a Blasius boundary layer describes the steady two-dimensional boundary layer that forms on a semi-infinite plate which is held parallel to a constant unidirectional flow U....
that forms on a semi-infinite
Semi-infinite
The term semi-infinite has several related meanings in various branches of pure and applied mathematics. It typically describes objects which are infinite or unbounded in some but not all possible ways.-In ordered structures and Euclidean spaces:...
plate that is held parallel to a constant unidirectional flow
.Blasius' theorem
For a steady fluid flow with complex potential around a fixed body enclosed by a contour , the net force on the body due to fluid motion is given by 
where
is the constant fluid density. This is a contour integral which may be computed by using Cauchy's residue theoremResidue theorem
The residue theorem, sometimes called Cauchy's Residue Theorem, in complex analysis is a powerful tool to evaluate line integrals of analytic functions over closed curves and can often be used to compute real integrals as well. It generalizes the Cauchy integral theorem and Cauchy's integral formula...
.
Correlations
First law of Blasius for turbulent fanning friction factor:
Second law of Blasius for turbulent fanning friction factor:
Law of Blasius for friction coefficient in turbulent pipe flow:
