The Strouhal number calculator compute the Strouhal number based on the frequency, characteristic length and flow velocity.
INSTRUCTIONS: Choose units and enter the following:
Strouhal number (St): The calculator returns the Strouhal number.
In dimensional analysis, the Strouhal number (St) 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. The Strouhal number is an integral part of the fundamentals of fluid mechanics.
The formula for the Strouhal number is:
St = (f • L) / U
where
The Strouhal number is used to characterize and predict the occurrence of vortex shedding and flow separation in various systems, such as flow around objects (like cylinders or airfoils) or in situations involving periodic fluid motion (like flapping wings or vibrating structures).
Applications of the Strouhal number include:
In practical terms, a particular Strouhal number range often signifies the onset of specific flow behaviors. For instance, for a flow around a cylinder, a Strouhal number around 0.2 to 0.3 often indicates the onset of significant vortex shedding.
Understanding the Strouhal number helps engineers and scientists in designing aerodynamic structures, predicting flow patterns, minimizing drag, optimizing performance, and avoiding undesired vibrations or oscillations in various engineering applications.