A criterion for the similarity of non-stationary motions of liquids or gases. The Strouhal number characterizes the identity of the flow of the processes in the course of time:
where $v$ is the typical velocity of the flow, $l$ is the typical linear dimension, $t$ is the typical period of time for non-stationary motion, and $\omega$ is the typical frequency (the inverse quantity $vt/l$ is sometimes also denoted by Sh).
The same criterion $H_0=vt/l$ in mechanical, thermal and electromagnetic processes is called the homochromity test.
The Strouhal number is named after V. Strouhal.
|[a1]||L.I. Sedov, "Similarity and dimensional methods in mechanics" , Acad. Press (1959) (Translated from Russian)|
Strouhal number. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Strouhal_number&oldid=33468