Scour Around Vertical Pile Foundations for Offshore Wind Turbines due to Long-Crested and Short-Crested Nonlinear Random Waves

2011 ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Offshore Wind ◽  
Wave Crest ◽  
Random Wave ◽  
Scour Depth ◽  
Height Distribution ◽  
Random Waves ◽  
Offshore Wind Turbines ◽  
Nonlinear Random Waves ◽  
Wave Induced ◽  
2D And 3D

This paper provides a practical stochastic method by which the maximum scour depth around vertical piles exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall (2000) wave crest height distribution representing both 2D and 3D nonlinear random waves, and using the regular wave formulas for scour depth by Sumer et al. (1992b). An example of calculation is provided. Tentative approaches to related random wave-induced scour cases are also suggested.

Scour Around Vertical Pile Foundations for Offshore Wind Turbines Due to Long-Crested and Short-Crested Nonlinear Random Waves

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Order Theory ◽  
Offshore Wind ◽  
Wave Crest ◽  
Random Wave ◽  
Scour Depth ◽  
Height Distribution ◽  
Random Waves ◽  
Equilibrium Scour Depth ◽  
Nonlinear Random Waves ◽  
Wave Induced

This paper provides a practical stochastic method by which the maximum equilibrium scour depth around vertical piles exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall wave crest height distribution (Forristall, 2000, “Wave Crest Distributions: Observations and Second-Order Theory,” J. Phys. Oceanogr., 30, pp. 1931–1943) representing both 2D and 3D nonlinear random waves, and using the regular wave formulas for scour depth by Sumer et al. (1992, “Scour Around Vertical Pile in Waves,” J. Waterway, Port, Coastal, Ocean Eng., 114(5), pp. 599–641). An example calculation is provided. Tentative approaches to related random wave-induced scour cases are also suggested.

scholarly journals Time Scale for Scour Beneath Pipelines Due to Long-Crested and Short-Crested Nonlinear Random Waves Plus Current

2021 ◽  
Vol 9 (2) ◽  
pp. 114
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Time Scale ◽  
Current Flow ◽  
Irregular Waves ◽  
Wave Crest ◽  
Random Wave ◽  
Random Waves ◽  
Flow Conditions ◽  
Regular Waves ◽  
Nonlinear Random Waves ◽  
2D And 3D

This article derives the time scale of pipeline scour caused by 2D (long-crested) and 3D (short-crested) nonlinear irregular waves and current for wave-dominant flow. The motivation is to provide a simple engineering tool suitable to use when assessing the time scale of equilibrium pipeline scour for these flow conditions. The method assumes the random wave process to be stationary and narrow banded adopting a distribution of the wave crest height representing 2D and 3D nonlinear irregular waves and a time scale formula for regular waves plus current. The presented results cover a range of random waves plus current flow conditions for which the method is valid. Results for typical field conditions are also presented. A possible application of the outcome of this study is that, e.g., consulting engineers can use it as part of assessing the on-bottom stability of seabed pipelines.

Burial and Scour of Short Cylinders and Truncated Cones Due to Long-Crested and Short-Crested Nonlinear Random Waves Plus Currents

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Muk Chen Ong ◽  
Dag Myrhaug
Keyword(s):  
Narrow Band ◽  
Three Dimensional ◽  
Wave Crest ◽  
Height Distribution ◽  
Random Waves ◽  
Regular Waves ◽  
Nonlinear Random Waves ◽  
2D And 3D ◽  
The Waves ◽  
Crest Height

This paper provides a practical stochastic method by which the burial and scour depths of short cylinders and truncated cones exposed to long-crested (two-dimensional (2D)) and short-crested (three-dimensional (3D)) nonlinear random waves plus currents can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall second-order wave crest height distribution representing both 2D and 3D nonlinear random waves. Moreover, the formulas for the burial and the scour depths for regular waves plus currents presented by previous published work for short cylinders and truncated cones are used.

Effects of Sand-Clay Mixtures on Scour Around Vertical Piles Due to Long-Crested and Short-Crested Nonlinear Random Waves

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Coastal Ocean ◽  
Stochastic Method ◽  
Offshore Wind ◽  
Pile Foundations ◽  
Scour Depth ◽  
Regular Wave ◽  
Random Waves ◽  
Offshore Wind Turbines ◽  
Equilibrium Scour Depth ◽  
Nonlinear Random Waves

This note provides a practical stochastic method by which the effects of sand-clay mixtures on the maximum equilibrium scour depth around vertical piles exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. This is made by using the regular wave formulas for scour depth for sand-clay mixtures by Dey et al. (2011, Scour at Vertical Piles in Sand-Clay Mixtures Under Waves,” J. Waterway, Port, Coastal, Ocean Eng., 137(6), pp. 324–331) and the stochastic method presented by Myrhaug and Ong (2013, “Scour Around Vertical Pile Foundations for Offshore Wind Turbines Due to Long-Crested and Short-Crested Nonlinear Random Waves,” ASME J. Offshore Mech. Arctic Eng., 135(1), p. 011103). Thus the present results are supplementary to those presented in the latter reference. An example calculation is provided.

Burial and Scour of Short Cylinders and Truncated Cones due to Long-Crested and Short-Crested Nonlinear Random Waves Plus Currents

2016 ◽  
Author(s):  
Muk Chen Ong ◽  
Dag Myrhaug
Keyword(s):  
Random Process ◽  
Narrow Band ◽  
Wave Crest ◽  
Height Distribution ◽  
Random Waves ◽  
Regular Waves ◽  
Nonlinear Random Waves ◽  
2D And 3D ◽  
The Waves ◽  
Crest Height

This paper provides a practical stochastic method by which the burial and scour depths of short cylinders and truncated cones exposed to long-crested (2D) and short-crested (3D) nonlinear random waves plus currents can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall [1] wave crest height distribution representing both 2D and 3D nonlinear random waves. Moreover, the formulas for the burial and the scour depths for regular waves plus currents presented by Catano-Lopera and Garcia [2, 3] for short cylinders and Catano-Lopera et al. [4] for truncated cones are used.

A stochastic method for wave run-up on slender circular cylinders due to long-crested and short-crested non-linear random waves

2011 ◽  
Vol 225 (4) ◽  
pp. 350-360
Author(s):  
D Myrhaug ◽  
P Hesten ◽  
L E Holmedal
Keyword(s):  
Stochastic Approach ◽  
Stochastic Method ◽  
Circular Cylinders ◽  
Wave Crest ◽  
Parameter Study ◽  
Height Distribution ◽  
Random Waves ◽  
Non Linear ◽  
Run Up ◽  
2D And 3D

A practical stochastic method for estimating the wave run-up height on a slender vertical circular cylinder for long-crested (two-dimensional (2D)) and short-crested (three-dimensional (3D)) non-linear random waves is provided. This is achieved by using the velocity stagnation head theory in conjunction with a stochastic approach. Here the waves are assumed to be a stationary narrow-band random process. The effects of non-linear waves are included by adopting the Forristall wave crest height distribution representing both 2D and 3D non-linear random waves. A parameter study is provided and, for both 2D and 3D non-linear random waves, the wave run-up height is larger than for linear random waves. In shallow water, when the water is sufficiently shallow, the maximum wave run-up height is larger for 3D waves than for 2D waves. Comparisons are also made with measurements of the maximum wave run-up heights for 2D random waves in a finite water depth by De Vos et al., and it appears that the data are well predicted if the predictions are calibrated with the data. Therefore the present approach represents a model which can be validated against and adjusted to field data.

scholarly journals Random Wave-Induced Burial and Scour of Short Cylinders and Truncated Cones on Mild Slopes

2017 ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Random Process ◽  
Narrow Band ◽  
Stochastic Approach ◽  
Random Wave ◽  
Scour Depth ◽  
Height Distribution ◽  
Regular Waves ◽  
Wave Height Distribution ◽  
Wave Induced ◽  
The Waves

A stochastic approach calculating the random wave-induced burial and scour depth of short cylinders and truncated cones on mild slopes is provided. It assumes the waves to be a stationary narrow-band random process and a wave height distribution for mild slopes is adopted, also using formulae for the burial and scour depths for regular waves on horizontal beds for short cylinders and for truncated cones. Examples of results are also provided.

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