Fetch Length Given Frequency At Spectral Peak Calculator

Formula Used:

\[ Fetch Length = \frac{(Wind Speed at Height of 10 m^3) \times \left(\frac{Frequency at Spectral Peak}{3.5}\right)^{-1/0.33}}{[g]^2} \]

Fetch Length:

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1. What is Fetch Length?

Fetch Length is the unobstructed distance that wind can travel over water in a constant direction. It is a critical parameter in oceanography and coastal engineering for wave prediction and analysis.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Fetch Length = \frac{(Wind Speed at Height of 10 m^3) \times \left(\frac{Frequency at Spectral Peak}{3.5}\right)^{-1/0.33}}{[g]^2} \]

Where:

\( Wind Speed at Height of 10 m \) — Wind speed measured at 10 meters above ground level (m/s)
\( Frequency at Spectral Peak \) — The frequency at which the wave energy spectrum peaks (Hz)
\( [g] \) — Gravitational acceleration constant (9.80665 m/s²)

Explanation: This formula calculates the fetch length based on wind speed and spectral peak frequency, which are key parameters in wave generation and development.

3. Importance of Fetch Length Calculation

Details: Accurate fetch length calculation is essential for predicting wave characteristics, coastal erosion studies, marine navigation safety, and offshore structure design.

4. Using the Calculator

Tips: Enter wind speed at 10m height in m/s and frequency at spectral peak in Hz. All values must be positive and valid for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: Why is fetch length important in wave prediction?
A: Fetch length directly influences wave height, period, and energy. Longer fetch lengths generally produce larger, more developed waves.

Q2: What are typical fetch length values?
A: Fetch lengths can range from a few meters in small lakes to thousands of kilometers in open oceans, depending on the water body and wind conditions.

Q3: How does wind speed affect fetch length?
A: Higher wind speeds over longer durations and distances result in greater fetch lengths and more developed wave conditions.

Q4: Are there limitations to this calculation method?
A: This method assumes ideal conditions and may need adjustments for complex coastlines, varying wind directions, or limited water depths.

Q5: How is spectral peak frequency measured?
A: Spectral peak frequency is typically determined through wave buoy measurements or spectral analysis of wave records.