Comparisons of Two Different Mixed Eulerian-Lagrangian Schemes Based on a Study of Flare-Slamming Hydrodynamics

1996 ◽  
Vol 118 (3) ◽  
pp. 174-183
Author(s):  
M. L. Wang ◽  
A. W. Troesch ◽  
B. Maskew
Keyword(s):  
Free Surface ◽  
Comparative Study ◽  
Numerical Simulations ◽  
Fourier Coefficients ◽  
Fully Nonlinear ◽  
Time Stepping ◽  
Time Histories ◽  
Nonlinear Free Surface ◽  
Simulated Time ◽  
Flare Slamming

A comparative study of two different mixed Eulerian-Lagrangian methods is presented. Representative numerical simulations of oscillatory flare-slamming flows are given. Computations based on these two different numerical schemes, i.e., a desingularized method using Rankine ring sources and a source-doublet panel method (e.g., USAERO/FSP©), are compared with experiments. Fourier coefficients of the simulated time histories and experimentally measured forces are given for detailed error comparisons. The numerical simulations demonstrate the ranges of applicability of these two methods. Both are shown to be efficient and robust time-stepping schemes for the fully nonlinear free-surface problem studied here.

scholarly journals Modelling of depth-induced wave breaking in a fully nonlinear free-surface potential flow model

2019 ◽  
Vol 154 ◽  
pp. 103579 ◽  
Author(s):  
Christos E. Papoutsellis ◽  
Marissa L. Yates ◽  
Bruno Simon ◽  
Michel Benoit
Keyword(s):  
Free Surface ◽  
Surface Potential ◽  
Potential Flow ◽  
Wave Breaking ◽  
Flow Model ◽  
Fully Nonlinear ◽  
Nonlinear Free Surface ◽  
Potential Flow Model

A Nonlinear Numerical Wave Tank and its Applications

2013 ◽  
Author(s):  
Hui Sun ◽  
Odd M. Faltinsen
Keyword(s):  
Free Surface ◽  
Horizontal Cylinder ◽  
The Body ◽  
Numerical Wave Tank ◽  
Wave Tank ◽  
Fully Nonlinear ◽  
Reflected Waves ◽  
Numerical Wave ◽  
Nonlinear Free Surface ◽  
Numerical Beach

A two-dimensional fully nonlinear numerical wave tank is developed by using a boundary element method (BEM). The water depth can be shallow or deep. The waves are generated by simulating a piston wave maker or by specifying the input velocity at the upstream boundary. Fully nonlinear free surface conditions are satisfied in the numerical simulations. In the downstream region, a numerical beach is employed to dissipate the wave energy to avoid waves reflecting from the vertical downstream boundary. When there is a body piercing the free surface, another numerical beach is applied upstream the body to damp out only the reflected waves from the body. Two different applications are presented in this paper. The first one is to compute the pressure and velocity at any point inside the wave field. The other application is to calculate the forces on a horizontal cylinder fixed on the free surface. This second application is related to the investigation of the hydrodynamic forces on the pontoon of a fish farm. Nonlinearities are significant since the wave amplitudes can be large relative to the wavelength and the dimension of the cylinder.

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.

Efficient Hybrid-Spectral Model for Fully Nonlinear Numerical Wave Tank

2013 ◽  
Author(s):  
Torben B. Christiansen ◽  
Harry B. Bingham ◽  
Allan P. Engsig-Karup ◽  
Guillaume Ducrozet ◽  
Pierre Ferrant
Keyword(s):  
Free Surface ◽  
Convergence Rates ◽  
Correction Method ◽  
Problem Size ◽  
Fully Nonlinear ◽  
Spectral Solution ◽  
Nonlinear Free Surface ◽  
Dirichlet To Neumann Operator ◽  
Fourier Collocation ◽  
Laplace Problem

A new hybrid-spectral solution strategy is proposed for the simulation of the fully nonlinear free surface equations based on potential flow theory. A Fourier collocation method is adopted horisontally for the discretization of the free surface equations. This is combined with a modal Chebyshev Tau method in the vertical for the discretization of the Laplace equation in the fluid domain, which yields a sparse and spectrally accurate Dirichlet-to-Neumann operator. The Laplace problem is solved with an efficient Defect Correction method preconditioned with a spectral discretization of the linearised wave problem, ensuring fast convergence and optimal scaling with the problem size. Preliminary results for very nonlinear waves show expected convergence rates and a clear advantage of using spectral schemes.

CFD Modeling of Fully Nonlinear Water Wave Tank

2009 ◽  
Author(s):  
Guangyu Wu ◽  
Owen H. Oakley
Keyword(s):  
Free Surface ◽  
Potential Flow ◽  
Wave Breaking ◽  
Water Wave ◽  
Surface Displacement ◽  
Wave Steepness ◽  
Wave Tank ◽  
Fully Nonlinear ◽  
Free Surface Displacement ◽  
Time Histories

In this study, we use CFD simulations to model a fully nonlinear water wave tank. Firstly, for validation purpose, regular waves with different wave steepness are simulated and the results are compared with the second-order potential flow solution for the free surface displacement time history at fixed locations, the instantaneous free surface spatial profiles, and the velocity and pressure fields under the free surface. It is shown that for small wave steepness, the CFD solutions agree very well with the second-order potential flow solutions while for large wave steepness, apparent differences between these two solutions are observed. The validation and fully nonlinear feature of the CFD solutions are therefore demonstrated. Secondly, plunging breaking waves are simulated using the CFD wave tank by focusing a large number of linear wave components at a prescribed time and location. The time histories and normalized variance of free surface displacement at various locations along the tank are obtained from the CFD simulation and compared to the lab experiments. In particular, the CFD results predict reasonably well the wave breaking location and the loss of energy flux due to wave breaking. Finally, a vertical circular cylinder is placed in the CFD wave tank to simulate the breaking wave impact on a fixed structure. The pressure time histories at various points on the cylinder surface are obtained for several cylinder locations with respect to the prescribed wave breaking point. The CFD results are compared with previous experiments and discussed.

scholarly journals A comparative study of two fast nonlinear free-surface water wave models

2011 ◽  
Vol 69 (11) ◽  
pp. 1818-1834 ◽  
Author(s):  
Guillaume Ducrozet ◽  
Harry B. Bingham ◽  
Allan P. Engsig-Karup ◽  
Félicien Bonnefoy ◽  
Pierre Ferrant
Keyword(s):  
Free Surface ◽  
Surface Water ◽  
Comparative Study ◽  
Water Wave ◽  
Wave Models ◽  
Nonlinear Free Surface
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