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Papers by WEIQIU CHEN

Coastal Engineering Proceedings

The average overtopping discharge is an important parameter for the design of flood defences. Sev... more The average overtopping discharge is an important parameter for the design of flood defences. Several empirical formulas are available for predicting the overtopping discharge at dikes. However, these empirical formulas often have their specific applicable conditions. To complement with the empirical methods, a numerical model has been developed using the open source CFD package OpenFOAM to model the wave overtopping at dikes. Systematic calibration and validation of the numerical model are performed. The influences of the mesh, solver, turbulence model and roughness height on the modelled results of the average overtopping discharge have been investigated during the model calibration. The simulations show that the turbulence model increases the accuracy of the numerical model for predicting the average overtopping discharge under wave breaking conditions. The calibrated model is then validated by comparing the modelled average overtopping discharges with the measured ones from the ...

Journal of Marine Science and Engineering, 2022

Wave overtopping can cause erosion on the landward slope due to high flow velocities and turbulen... more Wave overtopping can cause erosion on the landward slope due to high flow velocities and turbulence that cause high stresses on the cover. Innovative block revetments such as Grassblocks protect the subsoil of the dike against erosion. The blocks are permeable, which reduces the flow velocity and the pressures along the landward slope. The performance of these blocks is assessed in physical tests, which provides insights into the stability of the blocks. However, such experiments are expensive and accurate measurements are difficult due to highly turbulent conditions. Therefore, the goal of this study is to determine the hydrodynamic conditions at the dike cover caused by the wave run-up on the seaward slope and by the overtopping flow over the crest and landward slope. The geometry and wave conditions from the physical test at the Deltares Delta flume are implemented in an OpenFOAM® numerical model. Using the porousWaveFoam solver, a porous layer on the crest and landward slope is ...

Modelling wave overtopping for flood defence reliability, the outline of a research project.

Journal of Marine Science and Engineering, 2020

The average overtopping discharge is an important parameter for the design and reinforcement of d... more The average overtopping discharge is an important parameter for the design and reinforcement of dikes. Rock armour on the waterside slopes and berms of dikes is widely used to reduce the wave overtopping discharge by introducing slope roughness and dissipation of energy in the permeable armour layer. However, methods for estimating the influence of a rock berm and roughness of rock armour at dikes on the average overtopping discharge still need to be developed and/or validated. Therefore, this study aims to develop empirical equations to quantify the reductive influence of rock armour on wave overtopping at dikes. Empirical equations for estimating the effects of rock berms and roughness are derived based on the analysis of experimental data from new physical model tests. The influence of roughness of the rock armour applied on parts of waterside slopes is estimated by introducing the location weighting coefficients. Results show that the newly derived equations to predict the avera...

Coastal Engineering, 2021

Accurate calculation of wave overtopping is important for determining the required crest height a... more Accurate calculation of wave overtopping is important for determining the required crest height and geometry of a dike. Berms and roughness elements are widely used to reduce the average overtopping discharge at dikes while the reductive effects of berm and roughness are still not fully understood. Several empirical formulae are available to predict the overtopping rate at coastal structures. However, the extrapolation of these empirical formulae is not always applicable for complex structures (e.g. a dike that has a berm and/or roughness elements on the waterside slopes) or wave conditions that are outside the applicability of the empirical predictors. A 2D numerical model based on OpenFOAM® is set up in this study for predicting wave overtopping at dikes that have complex configurations with berms and roughness elements. The validation results show that this OpenFOAM® model is capable of reproducing the incident waves accurately and predicting the wave overtopping discharge with good accuracy. Subsequently, the numerical model is applied to study the reductive influence of a berm and protruding blocks on the mean overtopping discharge at dikes. The roughness of protruding blocks is incorporated by explicitly modelling the protrusions using refined mesh. The model shows reasonable behaviour of the reduction of wave overtopping influenced by a berm and roughness. This indicates the capabilities of the numerical model in the design and safety assessment of dikes.