scholarly journals A NONLINEAR NUMERICAL MODEL OF SURFACE AND INTERNAL WAVES AROUND VARIOUS PERMEABLE BREAKWATERS

2002 ◽  
Vol 18 ◽  
pp. 371-376
Author(s):  
Taro KAKINUMA
Keyword(s):  
Numerical Model ◽  
Internal Waves ◽  
Nonlinear Numerical Model

scholarly journals Spatially Broad Observations of Internal Waves in the Upper Ocean at the Hawaiian Ridge

2006 ◽  
Vol 36 (6) ◽  
pp. 1085-1103 ◽  
Author(s):  
Joseph P. Martin ◽  
Daniel L. Rudnick ◽  
Robert Pinkel
Keyword(s):  
Numerical Model ◽  
Energy Density ◽  
Potential Energy ◽  
Internal Waves ◽  
Upper Ocean ◽  
Mean Square ◽  
The South ◽  
South Side ◽  
Topographic Slope ◽  
Hawaiian Ridge

Abstract The density and current structure at the Hawaiian Ridge was observed using SeaSoar and Doppler sonar during a survey extending from Oahu to Brooks Banks. Across- and along-ridge changes in internal wave statistics in the upper ocean within 200 km of the ridge are investigated. Internal waves with trough-to-crest amplitude as large as 60 m and horizontal wavelength of about 50 km are observed repeatedly in across-ridge sections of potential density. Within 150 km of the ridge, kinetic and potential energy density exceed open-ocean values with maxima about 10 times Garrett–Munk levels. In the Kauai Channel (KC), the kinetic energy density is largest along an M2 internal tide ray. The ray originates at the northern edge of the ridge peak at a large across-ridge change in topographic slope and terminates at the ocean surface about 30–40 km south of the ridge peak. Kinetic and potential energy density are larger on the south side of the ridge at KC, the side with larger topographic slope. Energy density is also larger on the south side of the ridge at KC in numerical model results and on the side of steeper topographic slope in analytical model results. Along the ridge, the largest observed values of mean-square shear and mean-square slope of isopycnal depth are collocated with the largest energy density in numerical model results. Mean-square shear and mean-square slope increase with decreasing bottom depth and with increasing M2 barotropic tidal forcing.

Study of Nonlinear Internal Waves and Impact on Offshore Drilling Units

2011 ◽  
Author(s):  
Nishu V. Kurup ◽  
Shan Shi ◽  
Zhongmin Shi ◽  
Wenju Miao ◽  
Lei Jiang
Keyword(s):  
Numerical Model ◽  
South China Sea ◽  
Internal Wave ◽  
Internal Waves ◽  
South China ◽  
Andaman Sea ◽  
Offshore Drilling ◽  
Nonlinear Internal Waves ◽  
Drilling Operations ◽  
Drilling System

Internal waves near the ocean surface have been observed in many parts of the world including the Andaman Sea, Sulu Sea and South China Sea among others. The factors that cause and propagate these large amplitude waves include bathymetry, density stratification and ocean currents. Although their effects on floating drilling platforms and its riser systems have not been extensively studied, these waves have in the past seriously disrupted offshore exploration and drilling operations. In particular a drill pipe was ripped from the BOP and lost during drilling operations in the Andaman sea. Drilling riser damages were also reported from the south China Sea among other places. The purpose of this paper is to present a valid numerical model conforming to the physics of weakly nonlinear internal waves and to study the effects on offshore drilling semisubmersibles and riser systems. The pertinent differential equation that captures the physics is the Korteweg-de Vries (KdV) equation which has a general solution involving Jacobian elliptical functions. The solution of the Taylor Goldstein equation captures the effects of the pycnocline. Internal wave packets with decayed oscillations as observed from satellite pictures are specifically modeled. The nonlinear internal waves are characterized by wave amplitudes that can exceed 50 ms and the present of shearing currents near the layer of pycnocline. The offshore drilling system is exposed to these current shears and the associated movements of large volumes of water. The effect of internal waves on drilling systems is studied through nonlinear fully coupled time domain analysis. The numerical model is implemented in a coupled analysis program where the hull, moorings and riser are considered as an integrated system. The program is then utilized to study the effects of the internal wave on the platform global motions and drilling system integrity. The study could be useful for future guidance on offshore exploration and drilling operations in areas where the internal wave phenomenon is prominent.

scholarly journals Huge internal waves in the vicinity of the Spitsbergen Island (Barents Sea)

2011 ◽  
Vol 11 (3) ◽  
pp. 981-986 ◽  
Author(s):  
O. E. Kurkina ◽  
T. G. Talipova
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Internal Waves ◽  
Barents Sea ◽  
Stratified Fluid ◽  
High Latitudes ◽  
Barotropic Tide ◽  
Nonlinear Internal Waves ◽  
Total Height ◽  
The Barents Sea

Abstract. The generation of huge amplitude internal waves by the barotropic tide in the Barents Sea at high latitudes is examined using the numerical model of the Euler 2-D equations for incompressible stratified fluid. The area considered is located between the Spitsbergen (Svalbard) Island and the Franz-Victoria Trough with a cross-section of 350 km length. There are two underwater hills about 100–150 m high on the background depth of about 300 m. It is shown that intensive nonlinear internal waves with amplitudes up to 50 m and lengths of about 6–12 km are generated in this zone. The total height of such waves is huge and they must be considered as a significant factor of the environment in this basin.

A numerical model of the air flow above water waves. Part 2

1977 ◽  
Vol 82 (2) ◽  
pp. 349-369 ◽  
Author(s):  
P. R. Gent
Keyword(s):  
Energy Transfer ◽  
Numerical Model ◽  
Water Waves ◽  
Air Flow ◽  
Field Observations ◽  
Transfer Rates ◽  
Fractional Rate ◽  
Theoretical Predictions ◽  
The Waves ◽  
Nonlinear Numerical Model

Further results from the nonlinear numerical model of the air flow in a deep turbulent boundary layer above water waves described in Gent & Taylor (1976) are presented. The results are calculated with the surface roughness z0 both constant and varying with position along the wave. With the form used when z0 varies, the fractional rate |ζ| of energy transfer per radian advance in phase due to the working of the pressure forces is larger than for z0 constant both when the transfer is from wind to waves and when it is from waves to wind. The latter case occurs when the waves are travelling faster than, or against, the wind. The energy transfer rates are compared with other theoretical predictions and with recent field observations.

A Novel Application of the Thermal Probe: Nonlinear and Phase Change Problems

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
M. H. Adjali
Keyword(s):  
Thermal Conductivity ◽  
Parameter Estimation ◽  
Numerical Model ◽  
Phase Change ◽  
Estimation Technique ◽  
Thermal Probe ◽  
Temperature Dependent ◽  
Agar Gel ◽  
Nonlinear Numerical Model ◽  
Thermal Conductivities

This paper reports on a new application of the thermal probe in nonlinear systems. Whereas the thermal probe has been originally developed to determine the thermal conductivity in linear cases (where the thermophysical properties are considered independent of the temperature), the method used here exploits a direct nonlinear numerical model associated with a parameter estimation technique to determine temperature dependent thermal conductivities. It has been applied to a water-agar gel during phase change and the thermal conductivities within the corresponding temperature interval could be determined.

Evaluation of Piled Raft Performance Using a Verified 3D Nonlinear Numerical Model

2017 ◽  
Vol 35 (4) ◽  
pp. 1831-1845 ◽  
Author(s):  
Ahmed M. Alnuaim ◽  
Hany El Naggar ◽  
M. Hesham El Naggar
Keyword(s):  
Numerical Model ◽  
Piled Raft ◽  
Nonlinear Numerical Model
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