# Roshko number

﻿
Roshko number

In fluid mechanics, the Roshko number is a dimensionless number describing oscillating flow mechanisms. It is given as:

:$mathit\left\{Ro\right\} = \left\{St\right\} \left\{Re\right\} = \left\{f L^\left\{2\right\}over u\right\}$

where Ro is the dimensionless Roshko number, St is the dimensionless Strouhal number, Re is the Reynolds number, "f" is the frequency of vortex shedding, "L" is the characteristic length (for example hydraulic diameter) and "ν" is the kinematic viscosity of the fluid.

ee also

*Reynolds number
*Strouhal number

References

*Olim, A. M., Riethmuller, M. L., and Gameiro da Silva, M. C., 2002, "Flowfield characterization in the wake of a low-velocity heated sphere anemometer", "Exp. Fluids", 32, pp. 645-651.
*Ormieres, D., and Provansal, M., 1999, “Transition to turbulence in the wake of a sphere”, "Phys. Rev. Lett.", 83, pp. 80-83.

* [http://etd.caltech.edu/etd/available/etd-10302003-144124/ On the Development of Turbulent Wakes From Vortex Streets] PhD. Thesis by Anatol Roshko (hosted on Caltech Site).

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Strouhal number — In dimensional analysis, the Strouhal number is a dimensionless number describing oscillating flow mechanisms. Often, it is given as:: mathrm{Sr}= {f Lover v} where Sr is the dimensionless Strouhal number, f is the frequency of vortex shedding, L …   Wikipedia

• Nusselt number — In heat transfer at a boundary (surface) within a fluid, the Nusselt number is the ratio of convective to conductive heat transfer across (normal to) the boundary. Named after Wilhelm Nusselt, it is a dimensionless number. The conductive… …   Wikipedia

• Rayleigh number — In fluid mechanics, the Rayleigh number for a fluid is a dimensionless number associated with buoyancy driven flow (also known as free convection or natural convection). When the Rayleigh number is below the critical value for that fluid, heat… …   Wikipedia

• Magnetic Reynolds number — The Magnetic Reynolds number is a dimensionless group that occurs in magnetohydrodynamics. It gives an estimate of the effects of magnetic advection to magnetic diffusion, and is typically defined by: where U is a typical velocity scale of the… …   Wikipedia

• Morton number — For Morton number in number theory, see Morton number (number theory). In fluid dynamics, the Morton number (Mo) is a dimensionless number used together with the Eötvös number to characterize the shape of bubbles or drops moving in a surrounding… …   Wikipedia

• Keulegan–Carpenter number — The Keulegan–Carpenter number is important for the computation of the wave forces on offshore platforms. In fluid dynamics, the Keulegan–Carpenter number, also called the period number, is a dimensionless quantity describing the relative… …   Wikipedia

• Ohnesorge number — The Ohnesorge number, Oh, is a dimensionless number that relates the viscous forces to inertial and surface tension forces. It is defined as: Where μ is the liquid viscosity ρ is the liquid density σ is the surface tension L is the characteristic …   Wikipedia

• Dean number — The Dean number is a dimensionless group in fluid mechanics, which occurs in the study of flow in curved pipes and channels. It is named after the British scientist W. R. Dean, who studied such flows in the 1920s (Dean, 1927, 1928). Definition… …   Wikipedia

• Deborah number — The Deborah number is a dimensionless number, often used in rheology to characterize the fluidity of materials under specific flow conditions. It was originally proposed by Markus Reiner, a professor at Technion in Israel, inspired by a verse in… …   Wikipedia

• Stanton number — The Stanton number, St or CH, is a dimensionless number that measures the ratio of heat transferred into a fluid to the thermal capacity of fluid. It is used to characterize heat transfer in forced convection flows. where h = convection heat… …   Wikipedia

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.