Roshko number
Encyclopedia
In fluid mechanics
, the Roshko number is a dimensionless number describing oscillating flow mechanisms. It is named after the American Professor of Aeronautics Anatol Roshko
. It is defined as
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.
Fluid mechanics
Fluid mechanics is the study of fluids and the forces on them. Fluid mechanics can be divided into fluid statics, the study of fluids at rest; fluid kinematics, the study of fluids in motion; and fluid dynamics, the study of the effect of forces on fluid motion...
, the Roshko number is a dimensionless number describing oscillating flow mechanisms. It is named after the American Professor of Aeronautics Anatol Roshko
Anatol Roshko
Anatol Roshko is the Theodore von Karman Professor of Aeronautics, Emeritus, at the California Institute of Technology, Pasadena, CA.Dr. Roshko is known for his contributions to gas dynamics. He along with H. W. Liepmann is the co-author of the widely used textbook "Elements of Gasdynamics"...
. It is defined as
where Ro is the dimensionless Roshko number, St is the dimensionless Strouhal number
Strouhal number
In dimensional analysis, the Strouhal number is a dimensionless number describing oscillating flow mechanisms. The parameter is named after Vincenc Strouhal, a Czech physicist who experimented in 1878 with wires experiencing vortex shedding and singing in the wind...
, Re is the Reynolds number, f is the frequency of vortex
Vortex
A vortex is a spinning, often turbulent,flow of fluid. Any spiral motion with closed streamlines is vortex flow. The motion of the fluid swirling rapidly around a center is called a vortex...
shedding
Vortex shedding
Vortex shedding is an unsteady flow that takes place in special flow velocities . In this flow, vortices are created at the back of the body and detach periodically from either side of the body. See Von Kármán vortex street.Vortex shedding is caused when a fluid flows past a blunt object...
, L is the characteristic length (for example hydraulic diameter) and ν is the kinematic viscosity of the fluid.
External links
- On the Development of Turbulent Wakes From Vortex Streets PhD. Thesis by Anatol RoshkoAnatol RoshkoAnatol Roshko is the Theodore von Karman Professor of Aeronautics, Emeritus, at the California Institute of Technology, Pasadena, CA.Dr. Roshko is known for his contributions to gas dynamics. He along with H. W. Liepmann is the co-author of the widely used textbook "Elements of Gasdynamics"...
(hosted on Caltech Site).