scholarly journals Comparison between the Lagrangian and Eulerian Approach for Simulating Regular and Solitary Waves Propagation, Breaking and Run-Up

2021 ◽  
Vol 11 (20) ◽  
pp. 9421
Author(s):  
Diana De Padova ◽  
Lucas Calvo ◽  
Paolo Michele Carbone ◽  
Domenico Maraglino ◽  
Michele Mossa

The present paper places emphasis on the most widely used Computational Fluid Dynamics (CFD) approaches, namely the Eulerian and Lagrangian methods each of which is characterized by specific advantages and disadvantages. In particular, a weakly compressible smoothed particle (WCSPH) model, coupled with a sub-particle scale (SPS) approach for turbulent stresses and a new depth-integrated non-hydrostatic finite element model were employed for the simulation of regular breaking waves on a plane slope and solitary waves transformation, breaking and run-up. The validation of the numerical schemes was performed through the comparison between numerical and experimental data. The aim of this study is to compare the two modeling methods with an emphasis on their performance in the simulation of hydraulic engineering problems.

Author(s):  
Anna Lyhne Jensen ◽  
Lasse Rosendahl ◽  
Henrik Sørensen ◽  
Flemming Lykholt-Ustrup

Simulation of clogging effects caused by cloths in wastewater pumps enables a faster and cheaper design process of wastewater pumps, which potentially leads to a reduction in the occurrence of clogging. Four potential methods for cloth simulation are reviewed and the challenges of each method are identified and compared. These methods are the Arbitrary Lagrangian-Eulerian (ALE) method, Immersed Boundary (IB) method, Smoothed Particle Hydrodynamics (SPH) coupled with the Finite Element method (FEM), and Computational Fluid Dynamics (CFD) coupled with the Discrete Element method (DEM). Each method has advantages and disadvantages, and each of them may prove to be applicable for the application. The CFD-DEM approach is chosen for future work.


Author(s):  
Balázs Tóth

A three-dimensional weakly compressible Smoothed ParticleHydrodynamics (SPH) solver is presented and applied tosimulate free-surface solitary waves generated in a quasi twodimensionaldam-break experiment. Test cases are constructedbased on the measurement layouts of a dam-break experiment.The simulated wave propagation speeds are compared to theexact solutions of the Korteweg-de Vries (KdV) equation as afirst order theory, and to a second order iterative approximationinvestigated in the literature. Free surface shapes of differentsimulation cases are investigated as well. The results show goodagreement with the free surface shapes of the KdV equation aswell as with the second order approximation of solitary wavepropagation speeds.


2015 ◽  
Vol 779 ◽  
pp. 556-597 ◽  
Author(s):  
Nimish Pujara ◽  
Philip L.-F. Liu ◽  
Harry Yeh

The swash of solitary waves on a plane beach is studied using large-scale experiments. Ten wave cases are examined which range from non-breaking waves to plunging breakers. The focus of this study is on the influence of breaker type on flow evolution, spatiotemporal variations of bed shear stresses and run-up. Measurements are made of the local water depths, flow velocities and bed shear stresses (using a shear plate sensor) at various locations in the swash zone. The bed shear stress is significant near the tip of the swash during uprush and in the shallow flow during the later stages of downrush. In between, the flow evolution is dominated by gravity and follows an explicit solution to the nonlinear shallow water equations, i.e. the flow due to a dam break on a slope. The controlling scale of the flow evolution is the initial velocity of the shoreline immediately following waveform collapse, which can be predicted by measurements of wave height prior to breaking, but also shows an additional dependence on breaker type. The maximum onshore-directed bed shear stress increases significantly onshore of the stillwater shoreline for non-breaking waves and onshore of the waveform collapse point for breaking waves. A new normalization for the bed shear stress which uses the initial shoreline velocity is presented. Under this normalization, the variation of the maximum magnitudes of the bed shear stress with distance along the beach, which is normalized using the run-up, follows the same trend for different breaker types. For the uprush, the maximum dimensionless bed shear stress is approximately 0.01, whereas for the downrush, it is approximately 0.002.


Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave–structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.


2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Marin Marin ◽  
M. M. Bhatti

AbstractThe present study deals with the head-on collision process between capillary–gravity solitary waves in a finite channel. The present mathematical modeling is based on Nwogu’s Boussinesq model. This model is suitable for both shallow and deep water waves. We have considered the surface tension effects. To examine the asymptotic behavior, we employed the Poincaré–Lighthill–Kuo method. The resulting series solutions are given up to third-order approximation. The physical features are discussed for wave speed, head-on collision profile, maximum run-up, distortion profile, the velocity at the bottom, and phase shift profile, etc. A comparison is also given as a particular case in our study. According to the results, it is noticed that the free parameter and the surface tension tend to decline the solitary-wave profile significantly. However, the maximum run-up amplitude was affected in great measure due to the surface tension and the free parameter.


2018 ◽  
Vol 144 (2) ◽  
pp. 04017170
Author(s):  
Viljami Laurmaa ◽  
Marco Picasso ◽  
Gilles Steiner ◽  
Frederic M. Evers ◽  
Willi H. Hager
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