# What is prandtl number?

## Prandtl Number

The Prandtl number is a dimensionless number; the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity. It is named after the German physicist Ludwig Prandtl.

### Some articles on prandtl number:

Turbulent Prandtl Number
... The turbulent Prandtl number is a non-dimensional term defined as the ratio between the momentum eddy diffusivity and the heat transfer eddy diffusivity ... The simplest model for is the Reynolds analogy, which yields a turbulent Prandtl number of 1 ... of 0.85, but ranges from 0.7 to 0.9 depending on the Prandtl number of the fluid in question ...
Prandtl Number
... The Prandtl number is a dimensionless number the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity ... It is named after the German physicist Ludwig Prandtl ... Note that whereas the Reynolds number and Grashof number are subscripted with a length scale variable, the Prandtl number contains no such length scale ...
Sherwood Number
... The Sherwood number, (also called the mass transfer Nusselt number) is a dimensionless number used in mass-transfer operation ... analysis, it can also be further defined as a function of the Reynolds and Schmidt numbers For example, for a single sphere it can be expressed as where is the Sherwood number due only to natural convection and ... valuable to chemical engineers in situations where the Reynolds number and Schmidt number are readily available ...
Boundary Layer - Aerodynamics
... boundary layer was first defined by Ludwig Prandtl in a paper presented on August 12, 1904 at the third International Congress of Mathematicians in Heidelberg, Germany ... of the two thicknesses is governed by the Prandtl number ... If the Prandtl number is 1, the two boundary layers are the same thickness ...
Turbulent Prandtl Number - Consequences
... In the special case where the Prandtl number and turbulent Prandtl number both equal unity (as in the Reynolds analogy), the velocity profile and ... If the Prandtl number and turbulent Prandtl number are different from unity, then a solution is possible by knowing the turbulent Prandtl number so that ... Consequently, the turbulent Prandtl number has no meaning ...

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