Numerical Simulation of Irregular Wave Forces on a Horizontal Cylinder

2016 ◽  
Author(s):  
Ankit Aggarwal ◽  
Mayilvahanan Alagan Chella ◽  
Arun Kamath ◽  
Hans Bihs ◽  
Øivind Asgeir Arnsten
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Model ◽  
Circular Cylinder ◽  
Wave Generation ◽  
Numerical Results ◽  
Irregular Waves ◽  
Wave Forces ◽  
Ghost Cell ◽  
Irregular Wave

In the present study, the irregular wave forces on a fully submerged circular cylinder are investigated using the open-source computational fluid dynamics (CFD) model REEF3D. A complete three dimensional representation of the ocean waves requires the consideration of the sea surface as an irregular wave train with the random characteristics. The numerical model uses the incompressible Reynolds-averaged Navier-Stokes (RANS) equations together with the continuity equation to solve the fluid flow problem. Turbulence modeling is carried out using the two equation k-ω model. Spatial discretization is done using an uniform Cartesian grid. The level set method is used for computing the free surface. For time discretization, third-order total variation diminishing (TVD) Runge Kutta scheme is used. Ghost cell boundary method is used for implementing the complex geometries in the numerical model. MPI is used for the exchange of the value of a ghost cell. Relaxation method is used for the wave generation. The numerical model is validated for the irregular waves for a wave tank without any structure. Further, the numerical model is validated by comparing the numerical results with the experimental data for a fully submerged circular cylinder under regular waves and irregular waves. The numerical results are in a good agreement with the experimental data for the regular and irregular wave forces. The JONSWAP spectrum is used for the wave generation. The free surface features and kinematics around the cylinder is also presented and discussed.

Numerical Simulations of Regular and Irregular Wave Forces on a Horizontal Semi-Submerged Cylinder

2017 ◽  
Author(s):  
Shengnan Liu ◽  
Muk Chen Ong ◽  
Charlotte Obhrai ◽  
Sopheak Seng
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Simulations ◽  
Stokes Equations ◽  
Wave Length ◽  
Wave Structure ◽  
Numerical Results ◽  
Irregular Waves ◽  
Wave Forces ◽  
Submerged Cylinder

Two-dimensional (2D) numerical simulations have been performed using OpenFOAM (an open source CFD software package [1]) and waves2Foam (an OpenFOAM based add-on library for wave generations and absorption [2]) to investigate free surface waves past one fixed horizontally semi-submerged cylinder. The 2-D simulations are carried out by solving Navier-Stokes equations which are discretized based on finite volume method (FVM). Volume of Fluid (VOF) method is employed to capture the free surface in the numerical wave tank. Validation studies have been performed by comparing the numerical results of Stokes first-order wave past a semi-submerged circular cylinder with the published experimental data at different incident wave properties. The numerical results are in good agreement with the experimental data. Subsequently, regular and irregular waves past semi-submerged cylinder at different wave heights and the wave lengths are computed numerically to investigate the effect of the wave height and wave length on wave-structure interaction. The numerical results for irregular waves are compared with those induced by regular waves.

Numerical Modelling of Breaking Wave Interaction With a Group of Four Vertical Slender Cylinders in Square Arrangements

2016 ◽  
Author(s):  
Mayilvahanan Alagan Chella ◽  
Hans Bihs ◽  
Arun Kamath ◽  
Dag Myrhaug ◽  
Øivind Asgeir Arnsten
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Model ◽  
Numerical Modelling ◽  
Wave Interaction ◽  
Wave Force ◽  
Wave Forces ◽  
Breaking Wave ◽  
Square Configuration ◽  
Breaking Wave Forces

The main purpose of the study is to investigate the breaking wave interaction with a group of four circular cylinders. The physical process of wave breaking involves many parameters and an accurate numerical modelling of breaking waves and the interaction with a structure remain a challenge. In the present study, the open-source (Computational Fluid Dynamics) CFD model REEF3D is used to simulate the breaking wave interaction with the multiple cylinders. The numerical model is based on the incompressible Reynolds Averaged Navier-Stokes (RANS) equations, the level set method for the free surface and the k–ω model for turbulence. The model uses a 5th-order conservative finite difference WENO scheme for the convective discretization and a 3rd-order Runge-Kutta scheme for time discretization. The numerical model is validated with experimental data of large-scale experiments for the free surface elevation and the breaking wave force on a single cylinder. A good agreement is seen between the numerical results and experimental data. Two different configurations with four cylinders are examined: in-line square configuration and diamond square configuration. The breaking wave forces on each cylinder in the group are computed for the two cases and the results are compared with the breaking wave force on a single isolated cylinder. Further, the study investigates the water surface elevations and the free surface flow features around the cylinders. In general, the cylinders in both configurations experience the maximum forces lower than the maximum force on a single cylinder. The results of the present study show that the interference effects from the neighbouring cylinders in a group strongly influence the kinematics around and the breaking wave forces on them.

Breaking Wave Interaction With a Group of Four Vertical Slender Cylinders in Two Square Arrangements

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Mayilvahanan Alagan Chella ◽  
Hans Bihs ◽  
Arun Kamath ◽  
Dag Myrhaug ◽  
Øivind Asgeir Arntsen
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Model ◽  
Wave Interaction ◽  
Wave Force ◽  
Maximum Force ◽  
Wave Forces ◽  
Breaking Wave ◽  
Square Configuration ◽  
Breaking Wave Forces

The main purpose of the study is to investigate the breaking wave interaction with a group of four circular cylinders. The physical process of wave breaking involves many parameters, and an accurate numerical modeling of breaking waves and the interaction with a structure remain a challenge. In the present study, the open-source computational fluid dynamics (CFD) model REEF3D is used to simulate the breaking wave interaction with multiple cylinders. The numerical model is based on the incompressible Reynolds-averaged Navier–Stokes (RANS) equations, the level set method for the free surface, and the k–ω model for turbulence. The numerical model is validated with experimental data of large-scale experiments for the free surface elevation and the breaking wave force on a single cylinder. A good agreement is obtained between the numerical results and experimental data. Two different configurations with four cylinders are examined: in-line square configuration and diamond square configuration. For both configurations, three different tank widths and four different spacings between the cylinders are investigated. The breaking wave forces on each cylinder in the group are computed for each case for the two configurations, and the results are compared with the breaking wave force on a single isolated cylinder. Furthermore, the study investigates the water surface elevations and the free surface flow features around the cylinders. For the closely spaced cylinders in a relatively narrower tank, the cylinders in both configurations experience the maximum forces lower than the maximum force on a single cylinder. But for the widely spaced cylinder in a relatively wider tank, the forces are higher and lower for the upstream cylinders and downstream cylinders, respectively, than the maximum force on a single isolated cylinder. The results of the present study show that the interference effects from the neighboring cylinders in a group strongly influence the kinematics around and the breaking wave forces on them.

Computational Fluid Dynamics Simulations of Regular and Irregular Waves Past a Horizontal Semi-Submerged Cylinder

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Shengnan Liu ◽  
Muk Chen Ong ◽  
Charlotte Obhrai ◽  
Sopheak Seng
Keyword(s):  
Free Surface ◽  
Numerical Simulations ◽  
Wave Height ◽  
Stokes Equations ◽  
Wave Force ◽  
Numerical Results ◽  
Irregular Waves ◽  
Wave Forces ◽  
Regular Waves ◽  
Peak Period

Two-dimensional (2D) numerical simulations have been performed to investigate both regular and irregular waves past a fixed horizontally semisubmerged circular cylinder. The 2D simulations are carried out by solving Navier–Stokes equations discretized by finite volume method. Volume of fluid (VOF) method is employed to capture the free surface in the numerical wave tank (NWT). Validation studies have been performed by comparing the numerical results of free surface waves past the cylinder with the published experimental and numerical data. The present numerical results are in good agreement with both the experimental and the other numerical results in terms of hydrodynamic forces and free surface elevation. Subsequently, the effects of the wave height and the wavelength on wave–structure interaction are investigated by conducting numerical simulations on the regular and the irregular waves past a semisubmerged cylinder at different wave heights and the wavelengths. The averaged and maximum vertical wave forces on the cylinder increase with the increasing wave height. The numerical results for the irregular waves are compared with those induced by the regular waves in terms of the maximum and averaged vertical wave forces. When the significant wave height and the spectral peak period of the irregular waves are equal to the wave height and the wave period of the regular waves, the maximum vertical wave force induced by the irregular waves is larger than that induced by the regular waves, meanwhile, the average vertical wave forces have the contrary relationship.

Numerical Simulations of Tsunami Wave Generation by Submarine and Aerial Landslides Using RANS and SPH Models

2009 ◽  
Author(s):  
Kaushik Das ◽  
Ron Janetzke ◽  
Debashis Basu ◽  
Steve Green ◽  
John Stamatakos
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Simulations ◽  
Tsunami Wave ◽  
Wave Generation ◽  
Numerical Results ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Tsunami Waves ◽  
Time Histories

Tsunami wave generation by submarine and aerial landslides is examined in this paper. Two different two-dimensional numerical methods have been used to simulate the time histories of fluid motion, free surface deformation, shoreline movement, and wave runup from tsunami waves generated by aerial and submarine landslides. The first approach is based on the Navier-Stokes equation and the volume of fluid (VOF) method: the Reynolds Averaged Navier-Stokes (RANS)-based turbulence model simulates turbulence, and the VOF method tracks the free surface locations. The second method uses Smoothed Particle Hydrodynamics (SPH)—a numerical model based on a fully Lagrangian approach. In the current work, two-dimensional numerical simulations are carried out for a freely falling wedge representing the landslide and subsequent wave generations. Numerical simulations for the landslide-driven tsunami waves have been performed with different values of landslide material densities. Numerical results obtained from both approaches are compared with experimental data. Simulated results for both aerial and submerged landslides show the complex flow patterns in terms of the velocity field, shoreline evolution, and free-surface profiles. Flows are found to be strongly transient, rotational, and turbulent. Predicted numerical results for time histories of free-surface fluctuations and the runup/rundown at various locations are in good agreement with the available experimental data. The similarity and discrepancy between the solutions obtained by the two approaches are explored and discussed.

scholarly journals WAVE FORCES INDUCED BY IRREGULAR WAVES ON A VERTICAL CIRCULAR CYLINDER

1978 ◽  
Vol 1 (16) ◽  
pp. 144 ◽  
Author(s):  
Hajime Ishida ◽  
Yuichi Iwagaki
Keyword(s):  
Circular Cylinder ◽  
Laboratory Experiments ◽  
Large Diameter ◽  
Small Diameter ◽  
Diffraction Theory ◽  
Irregular Waves ◽  
Wave Forces ◽  
Irregular Wave ◽  
Water Level Variations ◽  
Particle Velocities

In order to examine the irregular wave forces on a small diameter cylinder, laboratory experiments have been conducted on water particle velocities and wave forces with various kinds of irregular waves. As the results, it is indicated that the time variation and the spectral distribution of wave forces can be calculated adequately from the water level variations by using the methods proposed by Reid1' and Borgman2' respectively. Moreover, with respect to the irregular wave forces on a large diameter cylinder, a new calculation method was shown by means of applying Reid's linear filters1' to MacCamy and Fuchs's diffraction theory.

A numerical study of breaking waves in the surf zone

1998 ◽  
Vol 359 ◽  
pp. 239-264 ◽  
Author(s):  
PENGZHI LIN ◽  
PHILIP L.-F. LIU
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Numerical Model ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Surf Zone ◽  
Breaking Waves ◽  
Numerical Results ◽  
Long Distance ◽  
The Mean

This paper describes the development of a numerical model for studying the evolution of a wave train, shoaling and breaking in the surf zone. The model solves the Reynolds equations for the mean (ensemble average) flow field and the k–ε equations for the turbulent kinetic energy, k, and the turbulence dissipation rate, ε. A nonlinear Reynolds stress model (Shih, Zhu & Lumley 1996) is employed to relate the Reynolds stresses and the strain rates of the mean flow. To track free-surface movements, the volume of fluid (VOF) method is employed. To ensure the accuracy of each component of the numerical model, several steps have been taken to verify numerical solutions with either analytical solutions or experimental data. For non-breaking waves, very accurate results are obtained for a solitary wave propagating over a long distance in a constant depth. Good agreement between numerical results and experimental data has also been observed for shoaling and breaking cnoidal waves on a sloping beach in terms of free-surface profiles, mean velocities, and turbulent kinetic energy. Based on the numerical results, turbulence transport mechanisms under breaking waves are discussed.

An implicit scheme for simulation of free surface non-Newtonian fluid flows on dynamically adapted grids

2021 ◽  
Vol 36 (3) ◽  
pp. 165-176
Author(s):  
Kirill Nikitin ◽  
Yuri Vassilevski ◽  
Ruslan Yanbarisov
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Fluid Flows ◽  
Numerical Results ◽  
Implicit Scheme ◽  
New Approach

Abstract This work presents a new approach to modelling of free surface non-Newtonian (viscoplastic or viscoelastic) fluid flows on dynamically adapted octree grids. The numerical model is based on the implicit formulation and the staggered location of governing variables. We verify our model by comparing simulations with experimental and numerical results known from the literature.

A numerical model for earthquake-induced hydrodynamic forces and wave forces on inclined circular cylinder

2020 ◽  
Vol 207 ◽  
pp. 107382 ◽  
Author(s):  
Piguang Wang ◽  
Xiaojing Wang ◽  
Mi Zhao ◽  
Xinglei Cheng ◽  
Xiuli Du
Keyword(s):  
Numerical Model ◽  
Circular Cylinder ◽  
Hydrodynamic Forces ◽  
Wave Forces

scholarly journals Numerical modeling of fluid resonance in narrow gaps of fixed rectangular structures

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401987230
Author(s):  
Ming-ming Liu ◽  
Rui-jia Jin ◽  
Zhen-dong Cui
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Stokes Equations ◽  
Theoretical Data ◽  
Numerical Results ◽  
Two Dimensional ◽  
Arbitrary Lagrangian Eulerian ◽  
Fluid Resonance ◽  
Resonance Wave ◽  
Narrow Gaps

A two-dimensional numerical model is developed to investigate the phenomenon of resonance in narrow gaps. Instead of using commonly used Volume of Fluid method to capture the free surface which is sometimes difficult to capture the geometric properties of the geometrically complicated interface, the free surface is traced by using Arbitrary Lagrangian–Eulerian method. The numerical model is based on the two-dimensional Reynolds-Averaged Navier–Stokes equations. The numerical model is validated against wave propagation in wave flume. Comparisons between the numerical results and available theoretical data show satisfactory agreements. Fluid resonance in narrow gaps of fixed rectangular structures are simulated. Numerical results show that resonance wave height and wave frequency for rectangle boxes with sphenoid corners is larger than for rectangle boxes.

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