Benchmarking Experiments for Wave Absorption Modeling

2015 ◽  
Author(s):  
Allan R. Magee ◽  
Varjola Nelko ◽  
Kian Yew Lim ◽  
Lup Wai Chew
Keyword(s):  
Absorption Efficiency ◽  
Numerical Wave Tank ◽  
Wave Absorption ◽  
Wave Flume ◽  
Dissipative Effects ◽  
Laboratory Flume ◽  
Laboratory Investigations ◽  
Numerical Wave ◽  
Wave Properties

Passive wave absorption is usually employed at the downstream end of a wave flume or basin to avoid the build-up of wave energy in the tank. However, absorption of waves is not perfect in physical tanks. A beach of different shape and/or composition can result in different absorption efficiency. Laboratory investigations of various passive beach configurations are costly and time-consuming. A more efficient approach is to perform studies using a numerical wave tank (NWT), which in turn requires empirical data to tune the dissipative effects. This study attempts to better understand the quality of waves simulated in a laboratory flume with a uniformly inclined porous beach and a parabolic-shaped solid beach. The data will be used to validate a newly-developed NWT with passive wave absorption. Different incident wave properties are examined and the reflection coefficient is calculated primarily with the two-probe method proposed by Goda & Suzuki (1976) and compared with other methods. An overview of the experiments, absorption analysis and numerical simulation is presented and discussed.

scholarly journals Numerical and Experimental Studies on a Three-Dimensional Numerical Wave Tank

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 6585-6593 ◽  
Author(s):  
Xiaojie Tian ◽  
Qingyang Wang ◽  
Guijie Liu ◽  
Wei Deng ◽  
Zhiming Gao
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave

Numerical Study of Wave Slamming on a Rectangular Slab

2012 ◽  
Vol 204-208 ◽  
pp. 4971-4977
Author(s):  
Ya Mei Lan ◽  
Wen Hua Guo ◽  
Yong Guo Li
Keyword(s):  
Numerical Study ◽  
Navier Stokes ◽  
Governing Equations ◽  
Reflected Waves ◽  
Rans Equations ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Wave Slamming ◽  
Numerical Wave ◽  
Rectangular Slab

The CFD software FLUENT was used as the foundation to develop the numerical wave flume, in which the governing equations are the Reynolds-averaged Navier-Stokes (RANS) equations and the standard k~ε turbulence model. The wave generating and absorbing were introduced into the RANS equations as the source terms using the relaxation approach. A new module of the wave generating and absorbing function, which is suitable for FLUENT based on the volume of fluid method (VOF), was established. Within the numerical wave flume, the reflected waves from the model within the computation domain can be absorbed effectively before second reflection appears due to the wave generating boundary. The computational results of the wave pressures on the bottom of the rectangular slab were validated for the different relative clearance by the experimental data. Good agreements were found.

Numerical Investigation of Focused Waves and Their Interaction With a Vertical Cylinder Using REEF3D

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Hans Bihs ◽  
Mayilvahanan Alagan Chella ◽  
Arun Kamath ◽  
Øivind Asgeir Arntsen
Keyword(s):  
Free Surface ◽  
Stokes Equations ◽  
Free Surface Flows ◽  
Surface Elevation ◽  
Numerical Wave Tank ◽  
Free Surface Elevation ◽  
Wave Tank ◽  
Numerical Wave ◽  
Focused Wave ◽  
The Impact

For the stability of offshore structures, such as offshore wind foundations, extreme wave conditions need to be taken into account. Waves from extreme events are critical from the design perspective. In a numerical wave tank, extreme waves can be modeled using focused waves. Here, linear waves are generated from a wave spectrum. The wave crests of the generated waves coincide at a preselected location and time. Focused wave generation is implemented in the numerical wave tank module of REEF3D, which has been extensively and successfully tested for various wave hydrodynamics and wave–structure interaction problems in particular and for free surface flows in general. The open-source computational fluid dynamics (CFD) code REEF3D solves the three-dimensional Navier–Stokes equations on a staggered Cartesian grid. Higher order numerical schemes are used for time and spatial discretization. For the interface capturing, the level set method is selected. In order to test the generated waves, the time series of the free surface elevation are compared with experimental benchmark cases. The numerically simulated free surface elevation shows good agreement with experimental data. In further computations, the impact of the focused waves on a vertical circular cylinder is investigated. A breaking focused wave is simulated and the associated kinematics is investigated. Free surface flow features during the interaction of nonbreaking focused waves with a cylinder and during the breaking process of a focused wave are also investigated along with the numerically captured free surface.

scholarly journals Spectral shapes and parameters from three different wave sensors

2021 ◽  
Author(s):  
Anne Karin Magnusson ◽  
Robert Jensen ◽  
Val Swail
Keyword(s):  
Frequency Spectra ◽  
Measurement Systems ◽  
Wave Measurements ◽  
Climate Monitoring ◽  
Production Platform ◽  
Wave Sensors ◽  
Central North Sea ◽  
Wave Forecasting ◽  
Wave Properties

AbstractThe quality of wave measurements is of primary importance for the validation of wave forecasting models, satellite wave calibration and validation, wave physics, offshore operations and design and climate monitoring. Validation of global wave forecasts revealed significant regional differences, which were linked to the different wave buoy systems used by different countries. To fully understand the differences between the wave measurement systems, it is necessary to go beyond investigations of the integral wave parameters height, period and direction, into the frequency spectra and the four directional Fourier parameters that are used to estimate the directional distribution. We here analyse wave data measured from three different sensors (non-directional Datawell Waverider buoy, WaveRadar Rex, Optech laser) operating at the Ekofisk oil production platform located in the central North Sea over a period of several months, with significant wave height ranging from 1 to 10 m. In general, all three sensors provide similar measurements of the integral wave properties and frequency spectra, although there are some significant differences which could impact design and operations, forecast verification and climate monitoring. For example, the radar underestimates energy in frequency bands higher than 8 s by 3–5%, swell (12.5–16 s) by 5–13%, while the laser has 1–2% more energy than the Waverider in the most energetic bands. Lee effects of structures are also estimated. Lower energy at the frequency tail with the radar has an effect on wave periods (they are higher); wave steepness is seen to be reduced by 10% in the wind seas. Goda peakedness and the unidirectional Benjamin-Feir index are also examined for the three sensors.

MOTION OF FLOATING CAISSON USING 3D NUMERICAL WAVE TANK

2021 ◽  
Vol 77 (2) ◽  
pp. I_775-I_780
Author(s):  
Atsushi TAKAGI ◽  
Masashi WATANABE ◽  
Taro ARIKAWA
Keyword(s):  
Numerical Wave Tank ◽  
Wave Tank ◽  
Numerical Wave

Global Hydroelastic Analysis of Pontoon-Type VLFS

2009 ◽  
Author(s):  
L. L. Jiao ◽  
M. Greco ◽  
O. M. Faltinsen
Keyword(s):  
Numerical Solutions ◽  
Parameter Analysis ◽  
Local Analysis ◽  
Two Dimensional ◽  
Numerical Wave Tank ◽  
Regular Waves ◽  
Hydroelastic Analysis ◽  
Air Cushion ◽  
Numerical Wave ◽  
Hydroelastic Response

A two-dimensional composite strategy given by Greco et al. [1] is applied to couple a linear global solution with a nonlinear local analysis. Globally a linear hydroelastic analysis is performed by an accurate Beam-On-Elastic-Foundation (BOEF) method. A parameter analysis of hydroelastic response of the structure is also carried out. Locally, a two-dimensional fully-nonlinear numerical wave tank (NWT) in combination with a Boundary Element Method (BEM) is developed to estimate the interaction between regular waves and the structure restrained from rigid and elastic motions. The effect of air cushion is considered. Present results are compared with experimental data and other numerical solutions.

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