Womersley number

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A Womersley number is a dimensionless number in biofluid mechanics. It is a dimensionless expression of the of pulsatile flow frequency in relation to viscous effects. It is named after John R. Womersley (1907-1958).

The Womersley number, usually denoted $α$ , can be written as

$\alpha = R \left( \frac{\omega}{\nu} \right)^{1/2} \, ,$

where $R$ is an appropriate length scale (for example the radius of a pipe), $ω$ is the angular frequency of the oscillations, and $ν$ is the kinematic viscosity of the fluid.

[edit] References

Womersley, J.R., "Method for the calculation of velocity, rate flow, and viscous drag in arteries when the pressure gradient is known," Journal of Physiology, Vol 127, 1955, pp. 553–563.