1. What is the Strouhal Number?

The Strouhal Number is a dimensionless number describing oscillating flow mechanisms, particularly vortex shedding in fluid dynamics. It characterizes the frequency of vortex formation behind bluff bodies like cylinders.

2. How Does the Calculator Work?

The calculator uses the Strouhal Number formula for cylinders:

Where:

• \( S \) — Strouhal Number (dimensionless)
• \( Re \) — Reynolds Number (dimensionless)

Explanation: This empirical formula relates the Strouhal number to the Reynolds number for flow around circular cylinders, describing the vortex shedding frequency.

3. Importance of Strouhal Number Calculation

Details: The Strouhal number is crucial for predicting vortex-induced vibrations in engineering structures, designing heat exchangers, and understanding fluid-structure interactions in various applications.

4. Using the Calculator

Tips: Enter the Reynolds Number (must be greater than 0). The calculator will compute the corresponding Strouhal Number for flow around cylinders.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of Strouhal numbers for cylinders?
A: For circular cylinders, Strouhal numbers typically range from 0.18 to 0.22 in the laminar vortex shedding regime.

Q2: How does Reynolds number affect the Strouhal number?
A: The Strouhal number generally increases with Reynolds number up to a certain point, then becomes relatively constant in the subcritical flow regime.

Q3: What are the applications of Strouhal number calculations?
A: Used in designing offshore structures, bridges, heat exchangers, and predicting flow-induced vibrations in various engineering systems.

Q4: Are there limitations to this formula?
A: This formula provides an approximation and may vary based on surface roughness, cylinder aspect ratio, and free-stream turbulence.

Q5: When is vortex shedding most pronounced?
A: Vortex shedding is most pronounced at Reynolds numbers between 300 and 3×10⁵, known as the subcritical flow regime.