scholarly journals Validation of RANS Modelling for Wave Interactions with Sea Dikes on Shallow Foreshores Using a Large-Scale Experimental Dataset

2020 ◽  
Vol 8 (9) ◽  
pp. 650 ◽  
Author(s):  
Vincent Gruwez ◽  
Corrado Altomare ◽  
Tomohiro Suzuki ◽  
Maximilian Streicher ◽  
Lorenzo Cappietti ◽  
...  
Keyword(s):  
Experimental Data ◽  
Data Model ◽  
Large Scale ◽  
Evaluation Method ◽  
Vertical Wall ◽  
Model Performance ◽  
Navier Stokes ◽  
Wave Interactions ◽  
Complex Processes ◽  
Repeated Test

In this paper, a Reynolds-averaged Navier–Stokes (RANS) equations solver, interFoam of OpenFOAM®, is validated for wave interactions with a dike, including a promenade and vertical wall, on a shallow foreshore. Such a coastal defence system is comprised of both an impermeable dike and a beach in front of it, forming the shallow foreshore depth at the dike toe. This case necessitates the simulation of several processes simultaneously: wave propagation, wave breaking over the beach slope, and wave interactions with the sea dike, consisting of wave overtopping, bore interactions on the promenade, and bore impacts on the dike-mounted vertical wall at the end of the promenade (storm wall or building). The validation is done using rare large-scale experimental data. Model performance and pattern statistics are employed to quantify the ability of the numerical model to reproduce the experimental data. In the evaluation method, a repeated test is used to estimate the experimental uncertainty. The solver interFoam is shown to generally have a very good model performance rating. A detailed analysis of the complex processes preceding the impacts on the vertical wall proves that a correct reproduction of the horizontal impact force and pressures is highly dependent on the accuracy of reproducing the bore interactions.

scholarly journals An Inter-Model Comparison for Wave Interactions with Sea Dikes on Shallow Foreshores

2020 ◽  
Vol 8 (12) ◽  
pp. 985
Author(s):  
Vincent Gruwez ◽  
Corrado Altomare ◽  
Tomohiro Suzuki ◽  
Maximilian Streicher ◽  
Lorenzo Cappietti ◽  
...  
Keyword(s):  
Large Scale ◽  
Model Comparison ◽  
Stokes Equations ◽  
Vertical Wall ◽  
Computational Cost ◽  
Model Performance ◽  
Wave Structure ◽  
Navier Stokes ◽  
Qualitative Comparison ◽  
Wave Flume

Three open source wave models are applied in 2DV to reproduce a large-scale wave flume experiment of bichromatic wave transformations over a steep-sloped dike with a mildly-sloped and very shallow foreshore: (i) the Reynolds-averaged Navier–Stokes equations solver interFoam of OpenFOAM® (OF), (ii) the weakly compressible smoothed particle hydrodynamics model DualSPHysics (DSPH) and (iii) the non-hydrostatic nonlinear shallow water equations model SWASH. An inter-model comparison is performed to determine the (standalone) applicability of the three models for this specific case, which requires the simulation of many processes simultaneously, including wave transformations over the foreshore and wave-structure interactions with the dike, promenade and vertical wall. A qualitative comparison is done based on the time series of the measured quantities along the wave flume, and snapshots of bore interactions on the promenade and impacts on the vertical wall. In addition, model performance and pattern statistics are employed to quantify the model differences. The results show that overall, OF provides the highest model skill, but has the highest computational cost. DSPH is shown to have a reduced model performance, but still comparable to OF and for a lower computational cost. Even though SWASH is a much more simplified model than both OF and DSPH, it is shown to provide very similar results: SWASH exhibits an equal capability to estimate the maximum quasi-static horizontal impact force with the highest computational efficiency, but does have an important model performance decrease compared to OF and DSPH for the force impulse.

scholarly journals EFFECTS OF WAVE BREAKING AND BEACH SLOPE ON TOE SCOUR IN FRONT OF A VERTICAL SEAWALL

2012 ◽  
Vol 1 (33) ◽  
pp. 122 ◽  
Author(s):  
Qingping Zou ◽  
Zhong Peng ◽  
Pengzhi Lin
Keyword(s):  
Structural Stability ◽  
Wave Breaking ◽  
Vertical Wall ◽  
Volume Of Fluid ◽  
Navier Stokes ◽  
Coastal Structures ◽  
Wave Interactions ◽  
Beach Slope ◽  
Major Threat ◽  
Sea Bed

Scour in front of coastal structures is a major threat to structural stability and safety of properties behind. In this study, a Reynolds Averaged Navier-Stokes Solver (RANS) is combined with a Volume of Fluid (VOF) (RANS-VOF) surface capturing scheme to investigate the wave interactions with a Seawall and its adjacent sea bed. The main objective is to investigate the effects of wave breaking and beach slope on toe scour in front of a vertical wall.

An Aerodynamic Investigation of an Isolated Stationary Formula 1 Wheel Assembly

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
John Axerio-Cilies ◽  
Emin Issakhanian ◽  
Juan Jimenez ◽  
Gianluca Iaccarino
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Turbulence Modeling ◽  
Cross Flow ◽  
Vortex Pair ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Flow Features ◽  
Large Scale Flow ◽  
Flow Blockage

The flowfield around a 60% scale stationary Formula 1 tire in contact with the ground in a closed wind tunnel at a Reynolds number of 500,000 was computationally examined in order to assess the accuracy of different turbulence modeling techniques and confirm the existence of large scale flow features. A simplified and replica tire model that includes all brake components was tested to determine the sensitivity of the wake to cross flow within the tire hub along with the flow blockage caused by the brake assembly. The results of steady and unsteady Reynolds averaged Navier-Stokes (URANS) equations and a large eddy simulation (LES) were compared with the experimental data. The LES closure and the RANS closure that accounted for unsteadiness with low eddy viscosity (unsteady kω-SST) matched closest to the experimental data both in point wise velocity comparisons along with location and intensity of the strong counter-rotating vortex pair dominating the far wake of the tire.

Multistage Simulation by an Adaptive Finite Element Approach Using Structured Grids

1999 ◽  
Vol 121 (2) ◽  
pp. 450-459 ◽  
Author(s):  
M. Sleiman ◽  
A. Tam ◽  
M. P. Robichaud ◽  
M. F. Peeters ◽  
W. G. Habashi
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Mesh Adaptation ◽  
Navier Stokes ◽  
Interface Plane ◽  
Adaptive Finite Element ◽  
Local Flow ◽  
Edge Based

This paper presents the application of a three-dimensional Navier-Stokes finite element code (NS3D) in the context of turbomachinery rotor-stator multistage interaction. A mixing-plane approach is used, in which boundary conditions at a common interface plane between adjacent blade rows are iteratively adjusted to yield a flow satisfying the continuity, momentum, and energy conservation equations, in an average sense. To further improve the solutions, a mesh adaptation technique then redistributes the mesh points of the structured grid within each component, according to an a posteriori edge-based error estimate based on the Hessian of the local flow solution. This matrix of second derivatives controls both the magnitude and direction of the required mesh movement at each node, is then implemented using an edge-based spring analogy. The methodology is demonstrated for two test cases with two types of data: a well-instrumented experimental large-scale rotating rig for a second stage compressor at UTRC and an actual engine. The latter, a two-stage compressor of a turboprop, has been only tested as a single-stage configuration, because of the quality of the experimental data available. All results compare well to the data and demonstrate the utility of the approach. In Particular, the mesh adaptation shows large improvements in agreement between the calculations and the experimental data.

Numerical Investigation of Sloshing in a Tank: Statistical Description of Experiments and CFD Calculations

2010 ◽  
Author(s):  
Bogdan Iwanowski ◽  
Marc Lefranc ◽  
Rik Wemmenhove
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Single Phase ◽  
Stokes Equations ◽  
Numerical Study ◽  
Point Of View ◽  
Navier Stokes ◽  
Two Phase ◽  
Statistical Point ◽  
Phase Liquid

Numerical study of liquid dynamics in an LNG tank is presented. The available data from large scale (1:10) sloshing experiments of 2D section of an LNG carrier reveal large scatter in recorded values of peak pressures. The experimental data is analysed from statistical point of view in order to obtain distributions of the pressure peaks. Then the entire experimental data record is reproduced numerically by CFD simulations and it is shown that pressure peaks obtained numerically display scatter of values as well. A statistical description of the numerically obtained record is provided and compared with description derived from the experimental data. The applied CFD code ComFLOW solves Navier-Stokes equations and uses an improved Volume of Fluid (iVOF) method to track movement of fluid’s free surface. Two different fluid models, single-phase (liquid+void) and two-phase (liquid+compressible gas) can be applied, the latter model being capable of simulating bubbles and gas entrapped in liquid. For low tank filling rate discussed in the paper (10%) the single-phase approach is sufficient. Comparison of statistical properties of experimental and numerical records is offered.

Evaluation of CMIP6 Models Toward Dynamical Downscaling Over Eight CORDEX Domains

2021 ◽  
Author(s):  
Meng-Zhuo Zhang ◽  
Zhongfeng Xu ◽  
Ying Han ◽  
Weidong Guo
Keyword(s):  
Model Selection ◽  
Large Scale ◽  
Evaluation Method ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Global Climate ◽  
Global Climate Model ◽  
Model Performance ◽  
Uncertainty Range ◽  
Multiple Variables

Abstract Both reliability and independence of global climate model (GCM) simulation are essential for model selection to generate a reasonable uncertainty range of dynamical downscaling simulations. In this study, we evaluate the performance and interdependency of 37 GCMs from the Coupled Model Intercomparison Project Phase 6 (CMIP6) in terms of seven key large-scale driving fields over eight CORDEX domains. A multivariable integrated evaluation method is used to evaluate and rank the models’ ability to simulate multiple variables in terms of their climatological mean and interannual variability. The results suggest that the model performance varies considerably with seasons, domains, and variables evaluated, and no model outperforms in all aspects. However, the multi-model ensemble mean performs much better than any individual model. Among 37 CMIP6 models, the MPI-ESM1-2-HR, FIO-ESM-2-0, and MPI-ESM1-2-LR rank top three due to their overall good performance across all domains. To measure the model interdependency in terms of multiple fields, we define the similarity of multivariate error fields between pairwise models. Our results indicate that the dependence exists between most of the CMIP6 models, and the models sharing the same idea or/and concept generally show less independence. Furthermore, we hierarchically cluster the top 15 models based on the similarity of multivariate error fields to facilitate the model selection. Our evaluation can provide useful guidance on the selection of CMIP6 models based on their performance and relative independence, which helps to generate a more reliable ensemble of dynamical downscaling simulations with reasonable inter-model spread.

COMMUNITY-CURATED DATA RESOURCES AND LARGE-SCALE DATA-MODEL SYNTHESES: THE CHILDREN OF COHMAP

2016 ◽  
Author(s):  
John W. Williams ◽  
◽  
Simon Goring ◽  
Eric Grimm ◽  
Jason McLachlan
Keyword(s):  
Data Model ◽  
Large Scale ◽  
Large Scale Data ◽  
Scale Data

scholarly journals Accessible Routes Integrating Data from Multiple Sources

2020 ◽  
Vol 10 (1) ◽  
pp. 7
Author(s):  
Miguel R. Luaces ◽  
Jesús A. Fisteus ◽  
Luis Sánchez-Fernández ◽  
Mario Munoz-Organero ◽  
Jesús Balado ◽  
...  
Keyword(s):  
Information System ◽  
Data Model ◽  
Large Scale ◽  
Heterogeneous Data ◽  
Multiple Sources ◽  
Heterogeneous Data Sources ◽  
Different Types ◽  
Software Sensors ◽  
The City

Providing citizens with the ability to move around in an accessible way is a requirement for all cities today. However, modeling city infrastructures so that accessible routes can be computed is a challenge because it involves collecting information from multiple, large-scale and heterogeneous data sources. In this paper, we propose and validate the architecture of an information system that creates an accessibility data model for cities by ingesting data from different types of sources and provides an application that can be used by people with different abilities to compute accessible routes. The article describes the processes that allow building a network of pedestrian infrastructures from the OpenStreetMap information (i.e., sidewalks and pedestrian crossings), improving the network with information extracted obtained from mobile-sensed LiDAR data (i.e., ramps, steps, and pedestrian crossings), detecting obstacles using volunteered information collected from the hardware sensors of the mobile devices of the citizens (i.e., ramps and steps), and detecting accessibility problems with software sensors in social networks (i.e., Twitter). The information system is validated through its application in a case study in the city of Vigo (Spain).

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 Process-Based Model Prediction of Coastal Dune Erosion through Parametric Calibration

2021 ◽  
Vol 9 (6) ◽  
pp. 635
Author(s):  
Hyeok Jin ◽  
Kideok Do ◽  
Sungwon Shin ◽  
Daniel Cox
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Model Performance ◽  
Coastal Dunes ◽  
Wave Transformation ◽  
Storm Event ◽  
Face Model ◽  
Dune Erosion ◽  
Simulation Performance ◽  
Sand Bar

Coastal dunes are important morphological features for both ecosystems and coastal hazard mitigation. Because understanding and predicting dune erosion phenomena is very important, various numerical models have been developed to improve the accuracy. In the present study, a process-based model (XBeachX) was tested and calibrated to improve the accuracy of the simulation of dune erosion from a storm event by adjusting the coefficients in the model and comparing it with the large-scale experimental data. The breaker slope coefficient was calibrated to predict cross-shore wave transformation more accurately. To improve the prediction of the dune erosion profile, the coefficients related to skewness and asymmetry were adjusted. Moreover, the bermslope coefficient was calibrated to improve the simulation performance of the bermslope near the dune face. Model performance was assessed based on the model-data comparisons. The calibrated XBeachX successfully predicted wave transformation and dune erosion phenomena. In addition, the results obtained from other two similar experiments on dune erosion with the same calibrated set matched well with the observed wave and profile data. However, the prediction of underwater sand bar evolution remains a challenge.

Sign in / Sign up

Export Citation Format

Share Document