JONSWAP Spectrum for Fetch-limited Seas Solution

STEP 0: Pre-Calculation Summary
Formula Used
Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2))
Ef = ((α*[g]^2)/((2*pi)^4*f^5))*(exp(-1.25*(f/fp)^-4)*γ)^exp(-((f/fp)-1)^2/(2*σ^2))
This formula uses 2 Constants, 1 Functions, 6 Variables
Constants Used
[g] - Gravitational acceleration on Earth Value Taken As 9.80665
pi - Archimedes' constant Value Taken As 3.14159265358979323846264338327950288
Functions Used
exp - n an exponential function, the value of the function changes by a constant factor for every unit change in the independent variable., exp(Number)
Variables Used
Frequency Energy Spectrum - Frequency Energy Spectrum refers to a representation of the distribution of energy across different frequencies within a system or environment.
Dimensionless Scaling Parameter - Dimensionless Scaling Parameter is a value used in mathematical or scientific models to scale or normalize variables without units. It is used in the JONSWAP spectrum for fetch-limited seas.
Wave Frequency - (Measured in Hertz) - Wave Frequency is the number of waves that pass a fixed point in a given amount of time.
Frequency at Spectral Peak - (Measured in Hertz) - Frequency at Spectral Peak is the number of occurrences of a repeating event per unit of time.
Peak Enhancement Factor - Peak Enhancement Factor is a ratio used to quantify the increase in force or load experienced by a structure during extreme events, such as storms or earthquakes.
Standard Deviation - Standard Deviation is a statistical measure used to quantify the amount of variation or dispersion of a set of data points from the mean (average).
STEP 1: Convert Input(s) to Base Unit
Dimensionless Scaling Parameter: 0.1538 --> No Conversion Required
Wave Frequency: 8 Kilohertz --> 8000 Hertz (Check conversion ​here)
Frequency at Spectral Peak: 0.013162 Kilohertz --> 13.162 Hertz (Check conversion ​here)
Peak Enhancement Factor: 5 --> No Conversion Required
Standard Deviation: 1.33 --> No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Ef = ((α*[g]^2)/((2*pi)^4*f^5))*(exp(-1.25*(f/fp)^-4)*γ)^exp(-((f/fp)-1)^2/(2*σ^2)) --> ((0.1538*[g]^2)/((2*pi)^4*8000^5))*(exp(-1.25*(8000/13.162)^-4)*5)^exp(-((8000/13.162)-1)^2/(2*1.33^2))
Evaluating ... ...
Ef = 2.89619819293977E-22
STEP 3: Convert Result to Output's Unit
2.89619819293977E-22 --> No Conversion Required
FINAL ANSWER
2.89619819293977E-22 2.9E-22 <-- Frequency Energy Spectrum
(Calculation completed in 00.020 seconds)

Credits

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Created by Mithila Muthamma PA
Coorg Institute of Technology (CIT), Coorg
Mithila Muthamma PA has created this Calculator and 2000+ more calculators!
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Verified by M Naveen
National Institute of Technology (NIT), Warangal
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Parametric Spectrum Models Calculators

JONSWAP Spectrum for Fetch-limited Seas
​ LaTeX ​ Go Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2))
Fetch Length given Frequency at Spectral Peak
​ LaTeX ​ Go Fetch Length = ((Wind Speed at Height of 10 m^3)*((Frequency at Spectral Peak/3.5)^-(1/0.33)))/[g]^2
Frequency at Spectral Peak
​ LaTeX ​ Go Frequency at Spectral Peak = 3.5*(([g]^2*Fetch Length)/Wind Speed at Height of 10 m^3)^-0.33
Phillip's Equilibrium Range of Spectrum for Fully Developed Sea in Deep Water
​ LaTeX ​ Go Phillip's Equilibrium Range of Spectrum = Constant B*[g]^2*Wave Angular Frequency^-5

JONSWAP Spectrum for Fetch-limited Seas Formula

​LaTeX ​Go
Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2))
Ef = ((α*[g]^2)/((2*pi)^4*f^5))*(exp(-1.25*(f/fp)^-4)*γ)^exp(-((f/fp)-1)^2/(2*σ^2))

What is JONSWAP Spectrum?

The JONSWAP spectrum is effectively a fetch-limited version of the Pierson-Moskowitz spectrum, except that the wave spectrum is never fully developed and may continue to develop due to non-linear wave-wave interactions for a very long time.

How to Calculate JONSWAP Spectrum for Fetch-limited Seas?

JONSWAP Spectrum for Fetch-limited Seas calculator uses Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2)) to calculate the Frequency Energy Spectrum, The JONSWAP Spectrum for Fetch-limited Seas is defined as a situation in which wave energy (or wave height) is limited by the size of the wave generation area (fetch). Frequency Energy Spectrum is denoted by Ef symbol.

How to calculate JONSWAP Spectrum for Fetch-limited Seas using this online calculator? To use this online calculator for JONSWAP Spectrum for Fetch-limited Seas, enter Dimensionless Scaling Parameter (α), Wave Frequency (f), Frequency at Spectral Peak (fp), Peak Enhancement Factor (γ) & Standard Deviation (σ) and hit the calculate button. Here is how the JONSWAP Spectrum for Fetch-limited Seas calculation can be explained with given input values -> 2.9E-22 = ((0.1538*[g]^2)/((2*pi)^4*8000^5))*(exp(-1.25*(8000/13.162)^-4)*5)^exp(-((8000/13.162)-1)^2/(2*1.33^2)).

FAQ

What is JONSWAP Spectrum for Fetch-limited Seas?
The JONSWAP Spectrum for Fetch-limited Seas is defined as a situation in which wave energy (or wave height) is limited by the size of the wave generation area (fetch) and is represented as Ef = ((α*[g]^2)/((2*pi)^4*f^5))*(exp(-1.25*(f/fp)^-4)*γ)^exp(-((f/fp)-1)^2/(2*σ^2)) or Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2)). Dimensionless Scaling Parameter is a value used in mathematical or scientific models to scale or normalize variables without units. It is used in the JONSWAP spectrum for fetch-limited seas, Wave Frequency is the number of waves that pass a fixed point in a given amount of time, Frequency at Spectral Peak is the number of occurrences of a repeating event per unit of time, Peak Enhancement Factor is a ratio used to quantify the increase in force or load experienced by a structure during extreme events, such as storms or earthquakes & Standard Deviation is a statistical measure used to quantify the amount of variation or dispersion of a set of data points from the mean (average).
How to calculate JONSWAP Spectrum for Fetch-limited Seas?
The JONSWAP Spectrum for Fetch-limited Seas is defined as a situation in which wave energy (or wave height) is limited by the size of the wave generation area (fetch) is calculated using Frequency Energy Spectrum = ((Dimensionless Scaling Parameter*[g]^2)/((2*pi)^4*Wave Frequency^5))*(exp(-1.25*(Wave Frequency/Frequency at Spectral Peak)^-4)*Peak Enhancement Factor)^exp(-((Wave Frequency/Frequency at Spectral Peak)-1)^2/(2*Standard Deviation^2)). To calculate JONSWAP Spectrum for Fetch-limited Seas, you need Dimensionless Scaling Parameter (α), Wave Frequency (f), Frequency at Spectral Peak (fp), Peak Enhancement Factor (γ) & Standard Deviation (σ). With our tool, you need to enter the respective value for Dimensionless Scaling Parameter, Wave Frequency, Frequency at Spectral Peak, Peak Enhancement Factor & Standard Deviation and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
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