Simulating three dimensional wave run-up over breakwaters covered by antifer units

Najafi-Jilani, A.; Niri, M. Zakiri; Naderi, Nader

doi:10.2478/ijnaoe-2013-0180

Cited by 14 publications

(4 citation statements)

References 7 publications

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“…In recent years several works were dedicated to the application of CFD to the study of different coastal structures (eg., [42], [24], [25] and [26]). This work presents one of the first applications of a three-dimensional CFD approach to simulate a semicircular breakwater, which is validated with experimental data.…”

Section: Discussionmentioning

confidence: 99%

Performance Assessment of a Semi-Circular Breakwater through CFD Modelling

Gomes

Pinho

Valente³

et al. 2020

JMSE

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Coastal defence works, such as breakwaters, are structures that aim to support the action of waves and dissipate their energy. Therefore, they provide conditions for stabilizing the coast, protecting ports, beaches and other coastal infrastructures and ecosystems. Semicircular breakwaters have been applied in different locations around the world due to their aesthetic advantages and high structural performance. Marine structures are subject to hydrodynamic actions normally estimated through physical models. However, these models are complex to implement, involving high costs and long experimental procedures. Thus, alternative methodologies for studying the hydrodynamic performance of these structures are of great use. This work presents the results of the application of a computational fluid dynamics (CFD) tool to study the stability of a perforated semicircular breakwater, based on a rubble mound foundation. The model was validated against experimental results of the critical weight necessary to resist sliding, taking into account the effects of water depth and different characteristics of the waves. A comparison is made between the perforated and the non-perforated solution in terms of the breakwater’s performance to dissipate wave energy. Dissipation conditions of this energy, in the exposed face, are also evaluated in detail, in order to assess the potential of this structure as a biological refuge for marine species. Both solutions show similar performance in terms of results obtained for the wave reflectivity coefficient. The turbulence dissipation on the exposed face of the perforated breakwater is limited to a region of restricted extension around it, which is advantageous in terms of the passage of species into the breakwater.

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Section: Discussionmentioning

confidence: 99%

Performance Assessment of a Semi-Circular Breakwater through CFD Modelling

Gomes

Pinho

Valente³

et al. 2020

JMSE

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“…On the other hand, increasing the number of mesh would in turn increase the computational times. To deal with this important issue, many users use local mesh block around complex geometries [31,32]. In this paper, based on the mesh independence study in the following sections, it is quite apparent that no mesh block is necessary and hence a single structured mesh is utilized.…”

Section: Meshmentioning

confidence: 99%

Investigating the Response Amplitude Operator of a Heaving Pontoon under the Influence of a Submerged Trapezoidal Breakwater

Ghadimi

Pourmostafa

Najafi

2020

Advances in Civil Engineering

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Although breakwaters are of great importance to damp the wave energy and protect floating vessels/facilities, they are not fully successful in reducing the waves’ height. Therefore, special attention should be paid to accurately investigate the performance of breakwaters. In this paper, the efficiency of a submerged trapezoidal breakwater in the vicinity of a floating pontoon is numerically investigated. First, different simulations are conducted to calibrate the numerical model to achieve an optimum mesh size. Next, a test case is presented for simulation of regular waves passing over a submerged breakwater. Subsequently, the heave response amplitude operator (RAO) of a rectangular pontoon facing an incoming regular wave is studied. A comparison of the obtained results in both test cases with experimental data shows good compliance. Ultimately, the heave motion of a rectangular pontoon behind four different submerged trapezoidal breakwaters facing a regular wave is investigated and different parametric studies are conducted to assess the geometrical effect of the breakwaters. This is the main novelty of the present work which studies the effect of a breakwater on the response amplitude operator (RAO) of a floating structure. In fact, a new version of RAO is presented which includes both incident and transferred wave (which pass over the breakwater) affecting the floating body. Based on the acquired results, the modified RAO of the heaving pontoon shows that breakwater has no effect on the responding frequency, but it does reduce the amplitude of the exciting wave up to 30%.

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“…Where is the input unit, is the network weight (from input unit to hidden unit ), and β is bias. The above equation ( ) is activation function [16]. One of the important activation functions is bipolar sigmoid function, which is defined as:…”

Section: Neural Network Modellingmentioning

confidence: 99%

“…These grooved cubes, Antifer-blocks called [5,6]. Among other works important documents were "wave run-up'' Battjes (1971) [7], van der meer (1992) [8], Van de Walle (2003) [9], Shanker et al (2003) [10], Hughes (2004) [12], , Dentale et al (2012) (2013) [14,15], Najafi-Jilani et al (2014) [16], Altomare et al (2014) [17], Crespo Alejandro [18], and Dong-Soo et al (2014) [19]. Furthermore, some of investigations have used SPH model to simulate wave run-up [18,19].…”

Section: Introductionmentioning

confidence: 99%

Wave Run-Up Prediction on Antifer Armor Using Neural Network Method

Rabiei

Najafi-Jilani

Niri

2014

Int. Conf. Coastal. Eng.

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The certainly goal of this study is to present the better way from terms of cost and experimenting duration, instead using experimental ways for investigates the wave run-up (Ru) over rubble-mound breakwater and examines the effect of placement pattern of Antifer units on the amount of wave run-up. In order to, it is suggested utilizing the Artificial Neural Networks (ANNs). For the sake of comparison, the proposed modeling is put into contrast by the ones obtained via other approaches in the literature. The Multi-Layer Perceptron (MLP) is selected as the artificial neural network exerted in this study. In the designed neural network, the numbers of inputs and outputs are selected as four and one, respectively. Additionally, the number of neurons in the single hidden layer of the network are appointed by trial and error. The Mean Square Error (MSE) of the training and correlating data set are investigated so that, seven hidden neurons is selected. This study has presented the regression equations and MSE for the results obtained by ANN are compared with other models. In conclusion, the regular placement would have offered to other placement patterns for the reason that its less MSE obtained by ANN.

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Simulating three dimensional wave run-up over breakwaters covered by antifer units

Cited by 14 publications

References 7 publications

Performance Assessment of a Semi-Circular Breakwater through CFD Modelling

Performance Assessment of a Semi-Circular Breakwater through CFD Modelling

Investigating the Response Amplitude Operator of a Heaving Pontoon under the Influence of a Submerged Trapezoidal Breakwater

Wave Run-Up Prediction on Antifer Armor Using Neural Network Method

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