Dynamic Response of Steel Catenary Riser in an Internal Wave Field

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Min Lou ◽  
Bing Tong ◽  
Yangyang Wang
Keyword(s):  
Dynamic Response ◽  
Internal Wave ◽  
Wave Field ◽  
Virtual Work ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Wave Load ◽  
Floating Platform ◽  
Steel Catenary Riser ◽  
Internal Wave Field

This paper proposes a dynamic model for steel catenary risers (SCRs) based on the principle of virtual work, where the equations of motion are obtained by combining Euler's equation and initial conditions. The motion equations of the floating platform are transformed and combined with those of the riser to establish the complete model. Vertical structure and dispersion of the internal wave are calculated to obtain the internal wave load and combined with the floating platform motion. The whole motion equation of the riser was solved by the Newmark β method. A proprietary matlab algorithm was written to analyze the influence of different factors on the dynamic response of the riser in an internal wave field. Top tension had a significant effect on the riser dynamic characteristics and response. Floating platform movement determines the vibration frequency of the riser, considering the internal wave as an external force, to promote the whole movement of the riser. The maximum riser displacement was mainly affected by the internal wave, where the top corner was mainly from the floating platform movement.

scholarly journals The internal wave field in Sau reservoir: Observation and modeling of a third vertical mode

2005 ◽  
Vol 50 (4) ◽  
pp. 1326-1333 ◽  
Author(s):  
Javier Vidal ◽  
Xavier Casamitjana ◽  
Jordi Colomer ◽  
Teresa Serra
Keyword(s):  
Internal Wave ◽  
Wave Field ◽  
Vertical Mode ◽  
Internal Wave Field

scholarly journals Internal Waves and Mixing near the Kerguelen Plateau

2015 ◽  
Vol 46 (2) ◽  
pp. 417-437 ◽  
Author(s):  
Amelie Meyer ◽  
Kurt L. Polzin ◽  
Bernadette M. Sloyan ◽  
Helen E. Phillips
Keyword(s):  
Internal Wave ◽  
Wave Field ◽  
Internal Waves ◽  
Large Scale ◽  
Polar Front ◽  
Frontal Region ◽  
Small Scale ◽  
Kerguelen Plateau ◽  
Flow Strength ◽  
Internal Wave Field

AbstractIn the stratified ocean, turbulent mixing is primarily attributed to the breaking of internal waves. As such, internal waves provide a link between large-scale forcing and small-scale mixing. The internal wave field north of the Kerguelen Plateau is characterized using 914 high-resolution hydrographic profiles from novel Electromagnetic Autonomous Profiling Explorer (EM-APEX) floats. Altogether, 46 coherent features are identified in the EM-APEX velocity profiles and interpreted in terms of internal wave kinematics. The large number of internal waves analyzed provides a quantitative framework for characterizing spatial variations in the internal wave field and for resolving generation versus propagation dynamics. Internal waves observed near the Kerguelen Plateau have a mean vertical wavelength of 200 m, a mean horizontal wavelength of 15 km, a mean period of 16 h, and a mean horizontal group velocity of 3 cm s−1. The internal wave characteristics are dependent on regional dynamics, suggesting that different generation mechanisms of internal waves dominate in different dynamical zones. The wave fields in the Subantarctic/Subtropical Front and the Polar Front Zone are influenced by the local small-scale topography and flow strength. The eddy-wave field is influenced by the large-scale flow structure, while the internal wave field in the Subantarctic Zone is controlled by atmospheric forcing. More importantly, the local generation of internal waves not only drives large-scale dissipation in the frontal region but also downstream from the plateau. Some internal waves in the frontal region are advected away from the plateau, contributing to mixing and stratification budgets elsewhere.

scholarly journals Bispectral Analysis of Energy Transfer within the Two-Dimensional Oceanic Internal Wave Field

2005 ◽  
Vol 35 (11) ◽  
pp. 2104-2109 ◽  
Author(s):  
Naoki Furuichi ◽  
Toshiyuki Hibiya ◽  
Yoshihiro Niwa
Keyword(s):  
Internal Wave ◽  
Wave Field ◽  
Internal Waves ◽  
Internal Tide ◽  
Energy Cascade ◽  
Minor Role ◽  
Two Dimensional ◽  
Bispectral Analysis ◽  
Internal Wave Field ◽  
Oceanic Internal Wave

Abstract Bispectral analysis of the numerically reproduced spectral responses of the two-dimensional oceanic internal wave field to the incidence of the low-mode semidiurnal internal tide is performed. At latitudes just equatorward of 30°, the low-mode semidiurnal internal tide dominantly interacts with two high-vertical-wavenumber diurnal (near inertial) internal waves, forming resonant triads of parametric subharmonic instability (PSI) type. As the high-vertical-wavenumber near-inertial energy level is raised by this interaction, the energy cascade to small horizontal and vertical scales is enhanced. Bispectral analysis thus indicates that energy in the low-mode semidiurnal internal tide is not directly transferred to small scales but via the development of high-vertical-wavenumber near-inertial current shear. In contrast, no noticeable energy cascade to high vertical wavenumbers is recognized in the bispectra poleward of ∼30° as well as equatorward of ∼25°. A new finding is that, although PSI is possible equatorward of ∼30°, the efficiency drops sharply as the latitude falls below ∼25°. At all latitudes, another resonant interaction suggestive of induced diffusion is found to occur between the low-mode semidiurnal internal tide and two high-frequency internal waves, although bispectral analysis shows that this interaction plays only a minor role in cascading the low-mode semidiurnal internal tide energy.

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