Full and Large Scale Wave Impact Tests for a Better Understanding of Sloshing: Results of the Sloshel Project

2011 ◽  
Author(s):  
Hannes Bogaert ◽  
Miroslaw Lech Mirek Kaminski ◽  
Laurent Brosset
Keyword(s):  
Preliminary Analysis ◽  
Large Scale ◽  
Structural Response ◽  
Full Scale ◽  
Breaking Wave ◽  
User Group ◽  
Wave Impact ◽  
Containment System ◽  
Peak Pressures ◽  
Physical Phenomena

This paper outlines the progress made within the Sloshel User Group in the analysis of unidirectional breaking wave impacts on transverse walls in flume tanks at full (1:1) and large (1:6) scales. These tests, carried out during the Sloshel project, were intended to help understanding the physics of sloshing impacts in tanks of LNG carriers and Floating LNG terminals (FLNGs). Two test campaigns were performed at full scale involving respectively the NO96 and the MarkIII containment systems. The latter was performed recently (April 2010) and the analysis is in progress. This paper describes the physical phenomena observed during the impacts on the MarkIII containment system. This helps understanding the difficulties inherent to the scaling of sloshing pressures measured during model tests. The paper also shows how important local peak pressures are for the structural response of the MarkIII system (same kind of conclusion had already been demonstrated for NO96 in Brosset, Mravak, Kaminski, Collins and Finnigan, 2009). According to very preliminary analysis, reduction of impact pressures due to hydro-elasticity with the MarkIII containment system seems to be moderated if real.

scholarly journals NUMERICAL MODELING OF TSUNAMI-INDUCED HYDRODYNAMIC FORCES ON ONSHORE STRUCTURES USING SPH

2012 ◽  
Vol 1 (33) ◽  
pp. 81 ◽  
Author(s):  
Philippe St-Germain ◽  
Ioan Nistor ◽  
Ronald Townsend
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Pressure Field ◽  
Hydrodynamic Forces ◽  
Small Scale ◽  
Breaking Wave ◽  
Total Force ◽  
Riemann Solver ◽  
Wave Impact ◽  
Time Histories

In this paper, the simulation of the violent impact of tsunami-like bores with a square column is performed using a single-phase, weakly compressible three-dimensional Smoothed Particle Hydrodynamics (SPH) model. In order to avoid large fluctuations in the pressure field and to obtain accurate simulations of the hydrodynamic forces, a Riemann solver-based formulation of the SPH method is utilized. Large-scale physical experiments conducted by the authors are reproduced using the numerical model. Time-histories of the water surface elevation as well as time-histories of the pressure distribution and net total force acting on the column are successfully compared. As observed in previous breaking wave impact studies, results show that the magnitude and duration of the impulsive force at initial bore impact depend on the degree of entrapped air in the bore-front. Although ensuring a stable pressure field, the Riemann solver-based SPH scheme is believed to induce excessive numerical diffusion, as sudden and large water surface deformations, such as splashing at initial bore impact, are marginally reproduced. To investigate this particular issue, the small-scale physical experiment of Kleefsman et al. (2005) is also considered and modeled.

Summary of the Joint Industry Project Wave Impact on Fixed Foundations (WiFi JIP)

2017 ◽  
Author(s):  
Erik Jan de Ridder ◽  
Tim Bunnik ◽  
Johan M. Peeringa ◽  
Bo Terp Paulsen ◽  
Christof Wehmeyer ◽  
...  
Keyword(s):  
State Of The Art ◽  
Full Scale ◽  
Offshore Wind ◽  
Water Model ◽  
Experimental Program ◽  
Breaking Wave ◽  
Wave Impact ◽  
Cfd Simulations ◽  
The North ◽  
The Impact

The objective of the Joint Industry Project Wave impact on Fixed foundations (WiFi JIP) was to increase the understanding of breaking and steep wave impact’s on fixed foundations of offshore wind turbines (OWT). The project was set-up as a Joint Industry Project (JIP) and in total 20 companies and research institutes participated in the project. In this paper a summary of the complete WiFi JIP project will be presented. At the start of the project the state of the art design methods and guidelines were reviewed (WP1). Thereafter a jacket and a monopile foundation were designed using these state-of-the-art tools that were available at the start of the project. This effort has been reported in WP2 , where design computations were carried out using the embedded stream function approach for several sea states. In this WP Siemens, ECN and Ramboll also calculated the impact response of the monopile to surging and spilling type wave breakers with their engineering tools. In the next phase the designed foundations were tested in MARIN’s shallow water model basin. The foundation for the monopile was modelled as a rigid and flexible foundation. The foundations were tested in regular waves, irregular sea states and so called focused waves. During the model tests the wave heights, wave run-up, accelerations, impact pressures and loads on the foundation and boat landing were measured. The model test results were reported in WP3 and 7 and used as validation for WP9 and 10. WP4 delivered more understanding of realistic design conditions for areas typical for OWT, like the North Sea. Particular attention was paid to the probability of occurrence of breaking and steep waves and the associated slamming load. For this an extensive 5 week experimental program was performed from September to October 2013 in the wide wave-current flume at Deltares (Atlantic Basin). During these tests both waves and current were simulated and two bathymetries. WP8 provided analyses of the performed full scale measurements on the response of a OWT. The full-scale measurements were done for a Vestas V90 3MW wind turbine in the Belwind windfarm which is located 46 km off the coast of Zeebrugge on the Bligh Bank. The CFD simulations performed in WP 9 showed that a good agreement is obtained between the CFD simulations and the model and full scale measurement. In work package 10, an improved methodology was developed based on the outcome of the previous WP’s to model the breaking wave impact of plunging type breakers. In WP11 and 12 this new approach is applied on different case study’s by ECN.

scholarly journals LARGE-SCALE PHYSICAL MODELLING OF A BROKEN SOLITARY WAVE IMPACT ON RIGID AND NON-RIGID BOX-LIKE STRUCTURES

2020 ◽  
pp. 19
Author(s):  
Clemens Krautwald ◽  
Jacob Stolle ◽  
Jan Hitzegrad ◽  
Peter Niebuhr ◽  
Nils Goseberg ◽  
...  
Keyword(s):  
Solitary Wave ◽  
Large Scale ◽  
Structural Response ◽  
Physical Modelling ◽  
Design Code ◽  
Wave Impact ◽  
Data Set ◽  
Unique Data ◽  
Pressure Distributions ◽  
First Time

Designing tsunami-safe buildings relies on engineering codes to estimate induced loads. The only such design code, written in mandatory language is "Chapter 6 - Tsunami Loads and Effects" published recently in the ASCE 7-16 (2017). In this study, for the first time, a bore originating from a solitary wave was used to investigate the damage to an idealized structure at relatively large scale (1:5). Therefore, model tests with rigid and non-rigid structures were combined to provide a unique data set of pressure distributions and structural response. This data set could be used to model structural behavior more realistically within the Froude-Cauchy similitude.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vVnEu9YIuQw

Hydroelastic effects in structural response under wave impact

2017 ◽  
Author(s):  
Liang-Yee Cheng ◽  
Rubens Augusto Amaro Junior
Keyword(s):  
Structural Response ◽  
Wave Impact

The Distribution of Breaking and Non-Breaking Wave Impact Forces

2009 ◽  
Author(s):  
Anne M. Fullerton ◽  
Ann Marie Powers ◽  
Don C. Walker ◽  
Susan Brewton
Keyword(s):  
Breaking Wave ◽  
Wave Impact ◽  
Impact Forces

scholarly journals Assessment of Numerical Methods for Plunging Breaking Wave Predictions

2021 ◽  
Vol 9 (3) ◽  
pp. 264
Author(s):  
Shanti Bhushan ◽  
Oumnia El Fajri ◽  
Graham Hubbard ◽  
Bradley Chambers ◽  
Christopher Kees
Keyword(s):  
Solitary Wave ◽  
Wave Breaking ◽  
Large Scale ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Wave Crest ◽  
Breaking Wave ◽  
Rans Turbulence Models ◽  
Run Up ◽  
Better Than

This study evaluates the capability of Navier–Stokes solvers in predicting forward and backward plunging breaking, including assessment of the effect of grid resolution, turbulence model, and VoF, CLSVoF interface models on predictions. For this purpose, 2D simulations are performed for four test cases: dam break, solitary wave run up on a slope, flow over a submerged bump, and solitary wave over a submerged rectangular obstacle. Plunging wave breaking involves high wave crest, plunger formation, and splash up, followed by second plunger, and chaotic water motions. Coarser grids reasonably predict the wave breaking features, but finer grids are required for accurate prediction of the splash up events. However, instabilities are triggered at the air–water interface (primarily for the air flow) on very fine grids, which induces surface peel-off or kinks and roll-up of the plunger tips. Reynolds averaged Navier–Stokes (RANS) turbulence models result in high eddy-viscosity in the air–water region which decays the fluid momentum and adversely affects the predictions. Both VoF and CLSVoF methods predict the large-scale plunging breaking characteristics well; however, they vary in the prediction of the finer details. The CLSVoF solver predicts the splash-up event and secondary plunger better than the VoF solver; however, the latter predicts the plunger shape better than the former for the solitary wave run-up on a slope case.

scholarly journals Influence of the Spatial Pressure Distribution of Breaking Wave Loading on the Dynamic Response of Wolf Rock Lighthouse

2021 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
Darshana T. Dassanayake ◽  
Alessandro Antonini ◽  
Athanasios Pappas ◽  
Alison Raby ◽  
James Mark William Brownjohn ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Pressure Distribution ◽  
Distinct Element ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Loading ◽  
Wave Impact ◽  
Pressure Distributions ◽  
Impact Area ◽  
The Impact

The survivability analysis of offshore rock lighthouses requires several assumptions of the pressure distribution due to the breaking wave loading (Raby et al. (2019), Antonini et al. (2019). Due to the peculiar bathymetries and topographies of rock pinnacles, there is no dedicated formula to properly quantify the loads induced by the breaking waves on offshore rock lighthouses. Wienke’s formula (Wienke and Oumeraci (2005) was used in this study to estimate the loads, even though it was not derived for breaking waves on offshore rock lighthouses, but rather for the breaking wave loading on offshore monopiles. However, a thorough sensitivity analysis of the effects of the assumed pressure distribution has never been performed. In this paper, by means of the Wolf Rock lighthouse distinct element model, we quantified the influence of the pressure distributions on the dynamic response of the lighthouse structure. Different pressure distributions were tested, while keeping the initial wave impact area and pressure integrated force unchanged, in order to quantify the effect of different pressure distribution patterns. The pressure distributions considered in this paper showed subtle differences in the overall dynamic structure responses; however, pressure distribution #3, based on published experimental data such as Tanimoto et al. (1986) and Zhou et al. (1991) gave the largest displacements. This scenario has a triangular pressure distribution with a peak at the centroid of the impact area, which then linearly decreases to zero at the top and bottom boundaries of the impact area. The azimuthal horizontal distribution was adopted from Wienke and Oumeraci’s work (2005). The main findings of this study will be of interest not only for the assessment of rock lighthouses but also for all the cylindrical structures built on rock pinnacles or rocky coastlines (with steep foreshore slopes) and exposed to harsh breaking wave loading.

scholarly journals Large-scale laboratory study of breaking wave hydrodynamics over a fixed bar

2017 ◽  
Vol 122 (4) ◽  
pp. 3287-3310 ◽  
Author(s):  
Dominic A. van der A ◽  
Joep van der Zanden ◽  
Tom O'Donoghue ◽  
David Hurther ◽  
Iván Cáceres ◽  
...  
Keyword(s):  
Laboratory Study ◽  
Large Scale ◽  
Breaking Wave
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