Numerical modeling of sediment scouring phenomenon around the offshore wind turbine pile in marine environment

Yamini, Omid Aminoroayaie; Mousavi, S. Hooman; Kavianpour, Mohammad Reza; Movahedi, Azin

doi:10.1007/s12665-018-7967-4

Cited by 43 publications

(13 citation statements)

References 19 publications

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“…The scour profile data must be normalized to provide for a comparison between varied experimental scales, and after a dimensional analysis of the governing quantities, it has been customary to non-dimensionalize the scour depth and the scour length by respectively employing the maximum scour depth, d sm , and the maximum scour length, L sm [36]. This results in demonstration of an appropriate match between the classical profiles including those of Lim and Chin [37], Aminoroaya et al [1,23] and others. Nonetheless, incorporating d sm and L sm entails restriction of data to intersect the origin, which is the point of the maximum scour and the maximum scour length, potentially hiding any differences between the tests and the role that small scale models could play.…”

Section: Equipment and Testing Methodsmentioning

confidence: 99%

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Experimental Modeling and Evaluation Sediment Scouring in Riverbeds around Downstream in Flip Buckets

Khalifehei

Azizyan

Shafai-Bajestan

et al. 2020

IJE

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Flip buckets are a common configuration for side channel spillways. Similar to other spillways, the flip bucket or ski jump has its disadvantages, among which the scour hole downstream due to the flip bucket jet is the most important. The structure safety and stability may be influenced by the scour holes generated at the downstream side of bucket type energy dissipators. This study has employed an experimental model in order to examine the sediment scour created at the end of flip bucket energy dissipators at various flow rates and tail water depths. A total of 45 experiments were performed under different conditions. The experimental invistigation was conducted at the hydraulic laboratory of Shahid Chamran University in Iran. The main objective of this research was to identify the maximum depth of sediment scour () and the maximum distance of sediment scour hole () from the structures. The results showed that the maximum depth of scour and its distance from the structure increased by increasing discharge. The results of experimental models show that, at the downstream depths () of 0.2 and 0.3 m, the stack was formed by the scouring at the upstream side of the hole, and at a depth of 0.1 m, this stack was transferred to the area after the scour hole. This could be explained by the fact that at downstream depths of 0.2 and 0.3 m, the rolling flow moved from the bottom upwards in the opposite direction of the water flow and sequestrated the sediments upstream. According to Equation Mean Absolute Relative Error (MARE) proposed relation based on laboratory studies has MARE of about 34.2%.

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Section: Equipment and Testing Methodsmentioning

confidence: 99%

“…These methods include rip-*Corresponding Author: kamran.khalifehei@pgs.usb.ac.ir (K. Khalifehei) rap, concrete block unit armor, articulated block mattress, gabions mattress, green coatings, stabilizers, etc. [1,2].…”

Section: Introductionmentioning

confidence: 99%

Experimental Modeling and Evaluation Sediment Scouring in Riverbeds around Downstream in Flip Buckets

Khalifehei

Azizyan

Shafai-Bajestan

et al. 2020

IJE

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“…To overcome these difficulties, the focus of researchers has turned to use Artificial Intelligence (AI) method for prediction of bridge pier scour depth. Recently, different artificial intelligence approaches such as artificial neural networks (ANN), adaptive Neuro-Fuzzy inference systems (ANFIS), genetic programming (GP), gene-expression programming (GEP), support vector machines (SVM), model trees (MT), evolutionary polynomial regressions (EPR), POS-SVM, multivariate adaptive regression splines (MARS), and self-adaptive extreme learning machines (SAELM) have been applied to predict the local scour depth around hydraulic structures [7][8][9][10][11][12][13][14][15][16]. Among these soft computing techniques, group method of data handling (GMDH) methods were widely applied to predict the local scour depth around bridge piers and abutments, downstream of ski-jump bucket spillways, downstream of grade-control structures, and below pipelines induced currents and waves [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers

Ghodsi

Khanjani

2020

Civ Eng J

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Scour depth prediction is a vital issue in bridge pier design. Recently, good progress has been made in the development of artificial intelligence (AI) to predict scour depth around hydraulic structures base such as bridge piers. In this study, two hybrid intelligence models based on combination of group method of data handling (GMDH) with harmony search algorithm (HS) and shuffled complex evolution (SCE) have been developed to predict local scour depth around complex bridge piers using 82 laboratory data measured by authors and 615 data points from published literature. The results were compared to conventional GMDH models with two kinds of transfer functions called GMDH1 and GMDH2. Based upon the pile cap location, data points were divided into three categories. The performance of all utilized models was evaluated by the statistical criteria of R, RMSE, MAPE, BIAS, and SI. Performances of developed models were evaluated by experimental data points collected in laboratory experiments, together with commonly empirical equations. The results showed that GMDH2SCE was the superior model in terms of all statistical criteria in training when the pile cap was above the initial bed level and completely buried pile cap. For a partially-buried pile cap, GMDH1SCE offered the best performance. Among empirical equations, HEC-18 produced relatively good performances for different types of complex piers. This study recommends hybrid GMDH models, as powerful tools in complex bridge pier scour depth prediction.

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“…However, this is the scenario for most engineering applications. Yamini et al [9] numerically investigated the sediment scouring phenomenon around the offshore wind turbine pile in marine environment.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations of the flow around four non-aligned circular cylinders

Kawaguti

Franzini

2020

Mar Syst Ocean Technol

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This works aims at numerically investigating the flow around a group of four non-aligned cylinders, for two different angles of incidence, β = 0° and 180° at Reynolds number (Re) equal to 200. The influence of the proximity between the cylinders is investigated by means of the numerical analysis based on Computational Fluid Dynamics (CFD), using a finite volume method with two-dimensional unstructured meshes. The distance between cylinders and the angle of incidence has a great influence on the flow behavior, which is reflected on the analysis of the force coefficients and the Strouhal number. At β = 0°, it is observed the presence of two regimes in the time series of the lift coefficient, which lifespan of the first regime is reduced with increase of the spacing ratio. Also, different drag coefficients were seen at spacing ratio equals to 3.5 D for the rear cylinders. Regarding to the results with β = 180°, they showed multiple peaks on the lift coefficient amplitude spectrum for the rear cylinders. This work contributes to enhance the understanding of the flow around multiple cylinders, mainly regarding non-traditional configurations such as tandem and side-by-side arrangements.

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Numerical modeling of sediment scouring phenomenon around the offshore wind turbine pile in marine environment

Cited by 43 publications

References 19 publications

Experimental Modeling and Evaluation Sediment Scouring in Riverbeds around Downstream in Flip Buckets

Experimental Modeling and Evaluation Sediment Scouring in Riverbeds around Downstream in Flip Buckets

Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers

Numerical investigations of the flow around four non-aligned circular cylinders

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