Diameter of Cylinder Given Strouhal Number Calculator

Formula Used:

\[ D_{vortex} = \frac{S \times V_{\infty}}{n} \]

Diameter of Cylinder with Vortex (Dvortex):

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1. What is the Vortex Shedding Diameter Formula?

The formula calculates the diameter of a cylinder experiencing vortex shedding in fluid flow. It relates the Strouhal number, freestream velocity, and vortex shedding frequency to determine the characteristic diameter of the cylinder.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ D_{vortex} = \frac{S \times V_{\infty}}{n} \]

Where:

\( D_{vortex} \) — Diameter of cylinder with vortex (m)
\( S \) — Strouhal Number (dimensionless)
\( V_{\infty} \) — Freestream Velocity of Fluid (m/s)
\( n \) — Frequency of Vortex Shedding (Hz)

Explanation: This formula describes the relationship between vortex shedding characteristics and the physical dimensions of a cylindrical object in fluid flow.

3. Importance of Vortex Shedding Calculation

Details: Accurate calculation of vortex shedding diameter is crucial for understanding flow-induced vibrations, structural design of cylindrical elements in fluid environments, and predicting potential resonance phenomena in engineering applications.

4. Using the Calculator

Tips: Enter Strouhal number (typically between 0.1-0.2 for cylinders), freestream velocity in m/s, and vortex shedding frequency in Hz. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Strouhal number?
A: For circular cylinders in cross-flow, the Strouhal number typically ranges from 0.18 to 0.22, with 0.21 being a common value for many applications.

Q2: How does Reynolds number affect vortex shedding?
A: The Strouhal number remains relatively constant over a wide range of Reynolds numbers (300 to 10^5), making this formula applicable across many flow conditions.

Q3: What are practical applications of this calculation?
A: This calculation is used in designing chimneys, offshore structures, heat exchanger tubes, and any cylindrical structures exposed to fluid flow to prevent destructive vibrations.

Q4: Can this formula be used for non-cylindrical shapes?
A: The formula is specifically derived for cylindrical shapes. Other shapes have different Strouhal number relationships and require different formulations.

Q5: How accurate is this calculation for real-world applications?
A: The formula provides a good estimation for engineering purposes, but actual conditions may vary due to surface roughness, turbulence intensity, and end effects.