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The Prandtl number (Pr) or Prandtl group is a dimensionless number, named after the German physicist Ludwig Prandtl, defined as the ratio of momentum diffusivity to thermal diffusivity. [1] The Prandtl number is given as:
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
The conventions of this class calculate the number of days between two dates (e.g., between Date1 and Date2) as the Julian day difference. This is the function Days(StartDate, EndDate). The conventions are distinguished primarily by the amount of the CouponRate they assign to each day of the accrual period.
In the situation of laminar flow in circular tubes, several dimensionless numbers are used such as Nusselt number, Reynolds number, and Prandtl number. The commonly used equation is =. Natural or free convection is a function of Grashof and Prandtl numbers. The complexities of free convection heat transfer make it necessary to mainly use ...
The turbulent Prandtl number (Pr t) is a non-dimensional term defined as the ratio between the momentum eddy diffusivity and the heat transfer eddy diffusivity. It is useful for solving the heat transfer problem of turbulent boundary layer flows. The simplest model for Pr t is the Reynolds analogy, which yields a
Or simply, using the simpler parameter names, compatible with {{Age in years, months and days}}: {{Age in years, months, weeks and days |month = 1 |day = 1 |year = 1 }} → 2023 years, 11 months, 2 weeks and 6 days; Alternatively, the first set of parameters can be left out to get the time left until a future date, such as the next Wikipedia ...
A Graetz number of approximately 1000 or less is the point at which flow would be considered thermally fully developed. [ 2 ] When used in connection with mass transfer the Prandtl number is replaced by the Schmidt number , Sc, which expresses the ratio of the momentum diffusivity to the mass diffusivity.
In continuum mechanics, the Péclet number (Pe, after Jean Claude Eugène Péclet) is a class of dimensionless numbers relevant in the study of transport phenomena in a continuum. It is defined to be the ratio of the rate of advection of a physical quantity by the flow to the rate of diffusion of the same quantity driven by an appropriate ...