GC Open #37 Traditional Cache

Vincenc Strouhal (10 April 1850 Seč - 23 January 1922 Prague) was an important Czech experimental physicist and professor who worked as a rector of Charles University in Prague.

Strouhal began studying at the grammar school at Hradec Králové at the age of 11, and after graduation he continued at the Faculty of Arts of Charles-Ferdinand University in Prague. During his studies he became a member of the unity of Czech mathematicians and physicists and as a student of the first year he presented his first lecture.

The Strouhal similarity number is named after him. Similarity numbers are used, for example, in aviation to compare the flow around the real aircraft and its model. The Strouhal's number determines the frequency of oscillations arising from the flow of the body with liquid. Strouhal related the frequency (f) of vortex formation behind the body, the characteristic dimension of the body (L) and the flow velocity (v), specifically Sr = f × L / v [-; Hz, M, m/s].

Why is the use of Strouhal's number practically significant?  Each flow break causes a change in the pressure distribution on the surface to be flowed around and is therefore accompanied by a change in the force effects on the body. A periodic current detachment can be pernicious if its frequency is the same as the natural frequency of the body. This phenomenon must be taken into account in buildings (chimneys, towers, suspension bridges), turbine blades, in heat exchangers, when anchoring masts, in telephone wires in the wind. There this phenomenon can cause, in many cases has already caused, an accident. In addition, the acoustic phenomena that accompany the detachment of a jet of air or liquid are annoying and can have devastating consequences. 

Strouhal habilitated in 1878 at the University of Würzburg. He worked on research on the thermoelectric and magnetic properties of steel with a small carbon addition, which was important for the production of permanent magnets. These results were published in the work "The electrical and magnetic properties of iron carburettes". "The Electrical and Magnetic Properties of the Iron-Carbureets".