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CALCULATOR MODULE : Ocean Wave And Current Velocity And Acceleration ±
Calculate ocean wave and current velocity and acceleration for Airy, Stokes, cnoidal and JONSWAP waves. Wave velocity and acceleration can be calculated for Airy, Stokes, and Cnoidal waves. The recommended wave type is displayed below the calc bar. Use the Result Plot option to compare the Airy, Stokes, and cnoidal wave profiles. The seabed significant wave velocity and zero upcrossing period can be calculated from the JONSWAP surface spectrum. Current velocity can be calculated near the seabed using either the logarithmic profile, or the 1/7th power law profile. The logarithmic and power law profiles are not valid For large elevations above the seabed. Note : The Stokes and cnoidal waves use trucated infinite series. Under certain conditions the truncated series do not converge properly. The Stokes wave is not suitable for shallow water waves. The cnoidal wave is not suitable for deep water waves. The recommended wave type is displayed below the calc bar. The JONSWAP wave uses an Airy wave transfer function to calculate seabed velocity. The JONSWAP wave is not suitable for very shallow waves (near breaking). Change Module : |
CALCULATOR MODULE : Ocean Wave Velocity And Acceleration ±
Calculate ocean wave velocity and acceleration for Airy, Stokes, cnoidal and JONSWAP waves. Wave velocity and acceleration can be calculated for Airy, Stokes, and Cnoidal waves. The recommended wave type is displayed below the calc bar. Use the Result Plot option to compare the Airy, Stokes, and cnoidal wave profiles. The seabed significant wave velocity and zero upcrossing period can be calculated from the JONSWAP surface spectrum. Note : The Stokes and cnoidal waves use trucated infinite series. Under certain conditions the truncated series do not converge properly. The Stokes wave is not suitable for shallow water waves. The cnoidal wave is not suitable for deep water waves. The recommended wave type is displayed below the calc bar. The JONSWAP wave uses an Airy wave transfer function to calculate seabed velocity. The JONSWAP wave is not suitable for very shallow waves (near breaking). Change Module : |
CALCULATOR MODULE : Ocean Wave Probability And Return Period ±
Calculate ocean wave height and period from return period data using the Weibull, Gumbel or Frechet probability distributions. The three parameter distribution and Z offset is used to account for a minimum value, the smallest event which can occur in any sample period. The best fit line is calculated for the data points using the least squares linear regression method. The regression is calculated for return period versus amplitude (the X and Z values are swapped). The regression data points and regression parameters are displayed in the output view at the bottom of the page. Change Module : Related Modules : |
CALCULATOR MODULE : Ocean Wave And Current Probability And Return Period ±
Calculate ocean wave height, wave period and current velocity from return period data using the Weibull, Gumbel or Frechet probability distributions. The three parameter distribution and Z offset is used to account for a minimum value, the smallest event which can occur in any sample period. The best fit line is calculated for the data points using the least squares linear regression method. The regression is calculated for return period versus amplitude (the X and Z values are swapped). Use the Data Plot option on the plot bar to display the data points and the calculated best fit. The regression data points and regression parameters are displayed in the output view at the bottom of the page. Change Module : Related Modules : |
CALCULATOR MODULE : JONSWAP Wave Spectrum ±
Calculate JONSWAP wave surface spectral density, and seabed velocity spectrum. The seabed velocity spectrum is calculated using a first order Airy wave transformation. Reference : Hasselmann K et al : Measurements of Wind-Wave Growth And Swell Decay During The Joint North Sea Wave Project (JONSWAP) Change Module : |
CALCULATOR MODULE : JONSWAP Wave Velocity And Period ±
Calculate JONSWAP wave seabed velocity and zero upcrossing period from spectral moments. The seabed velocity and upcrossing period is calculated using a first order Airy wave transformation. The Airy wave transformation may not be valid in shallow water. The calculation has been optimised for elevations on or near the seabed, and is not recommended for elevations greater than half the water depth. Return period data can be analysed using either the Weibull, Gumbel or Frechet distribution. Reference : Hasselmann K et al : Measurements of Wind-Wave Growth And Swell Decay During The Joint North Sea Wave Project (JONSWAP) Change Module : |
CALCULATOR MODULE : JONSWAP Wave Directionality And Spreading ±
Calculate JONSWAP wave spreading and velocity reduction factor from relative heading and spreading factor. Wave spreading accounts for the effect of short crested "choppy" waves with non uniform velocity and heading. By comparison, long ocean swells tend to have uniform velocity and direction, expecially in mid ocean. Use small spreading factors for "choppy" waves, and large spreading factors for ocena swells. Reference : Hasselmann K et al : Measurements of Wind-Wave Growth And Swell Decay During The Joint North Sea Wave Project (JONSWAP) Change Module : |
CALCULATOR MODULE : JONSWAP Combined Wave And Current Velocity ±
Calculate JONSWAP seabed wave and current amplitude from return period data. Return period data can be analysed using either the Weibull, Gumbel or Frechet distribution. Current velocity can be calculated using either the logarithmic profile, or the 1/7th power law profile. The logarithmic and power law profiles are only valid in the boundary layer on or near the seabed. The seabed velocity and upcrossing period is calculated from the JONSWAP surface spectrum using a first order Airy wave transformation. The calculation may not be valid in shallow water, and is not recommended for elevations greater than half the water depth. Reference : Hasselmann K et al : Measurements of Wind-Wave Growth And Swell Decay During The Joint North Sea Wave Project (JONSWAP) Change Module : |
CALCULATOR MODULE : DNVGL RP F109 Submarine Pipeline Stability ±
Calculate DNVGL-RP-F109 pipeline lateral and vertical stability. Static or absolute stability can be calculated for clay seabed, sandy seabed (D50 ≤ 50 mm), or rocky seabed (D50 > 50 mm). The single oscillation velocity corresponds to the maximum wave velocity in the return period. Maximum current velocity data should be used. Dynamic stability can be calculated on clay and sandy seabeds for Lstable (pipe displacement ≤ 0.5 OOD), L10 (pipe displacement ≤ 0.5 OOD), or user defined pipe displacement. Significant current velocity data should be used. Seabed wave velocity is calculated from the JONSWAP surface spectrum with an Airy wave transfer function. The calculation should only be used for elevations at or near the seabed. The Airy wave transform may not be valid in shallow water. Reference : DNVGL-RP-F109 : On-Bottom Stability Design Of Submarine Pipelines (Download from the DNVGL website) Change Module : |
CALCULATOR MODULE : DNVGL RP F109 Wave Spreading And Directionality ±
Calculate DNVGL RP-F109 wave spreading and directionality from relative heading and spreading factor. The wave spreading factor accounts for the "choppiness" or multi directional properties of wave groups. Locally generated waves are generally more multi directional and should have small spreading factors. Long range swells tend to be more uni directional, and can be used with large spreading factors. Reference : DNVGL-RP-F109 : On-Bottom Stability Design Of Submarine Pipelines (Download from the DNVGL website) Change Module : |
CALCULATOR MODULE : DNVGL RP F109 Wave Seabed Velocity ±
Calculate DNVGL RP-F109 wave seabed velocity from the JONSWAP surface spectrum. An Airy wave transform is used to calculate the significant seabed velocity, and zero upcrossing wave period. The calculation is not valid in shallow water, or at elevations greater than half the water depth. Reference : DNVGL-RP-F109 : On-Bottom Stability Design Of Submarine Pipelines (Download from the DNVGL website) Change Module : |
CALCULATOR MODULE : DNVGL RP F109 Wave Probability And Return Period ±
Calculate DNVGL RP-F109 wave and current amplitude from return period data. Current velocity, wave height, and wave period can be calculated from return period data using either the Weibull, Gumbel or Frechet probability distributions. Enter data as comma or tab separated sets (eg R, Vc), with each set on a new row. Data can also be copied and pasted from a spreadsheet, or from a text document. Reference : DNVGL-RP-F109 : On-Bottom Stability Design Of Submarine Pipelines (Download from the DNVGL website) Change Module : |