Numerical investigation on the wave dissipating performance due to multiple porous structures

Venkateswarlu, V.; Karmakar, D.

doi:10.1080/09715010.2019.1615393

Cited by 18 publications

(6 citation statements)

References 44 publications

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“…In our case, the largest bed roughness for gravel particles induces a flow retardation, which may also be increased by higher percolation, leading to a loss of swash volume. Both processes contribute to limit the runup, explaining that the porous structures are widely used as breakwaters for coastal defence (Guo et al, 2020; Twu & Chieu, 2000; Venkateswarlu & Karmakar, 2019). In addition, as indicated by Poate et al (2016), while these equations fit the range of gravel beach field data, the inclusion of a dimensional constant ( C ) implies that the equations can only be used for conditions similar to those in the field and model dataset.…”

Section: Discussionmentioning

confidence: 99%

“…In our case, the largest bed roughness for gravel particles induces a flow retardation, which may also be increased by higher percolation, leading to a loss of swash volume. Both processes contribute to limit the runup, explaining that the porous structures are widely used as breakwaters for coastal defence (Guo et al, 2020;Twu & Chieu, 2000;Venkateswarlu & Karmakar, 2019). In addition, as proposed to distinguish the different regimes of Orford and Carter's storm impact scale model (Orford & Carter, 1982).…”

Section: Calibration Of Runup Formulamentioning

confidence: 99%

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Catastrophic overwash and rapid retreat of a gravel barrier spit during storm events (Sillon de Talbert, North Brittany, France)

Suanez

Stéphan

Autret

et al. 2022

Earth Surf Processes Landf

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The morphodynamic functioning of the Sillon de Talbert gravel barrier spit is analysed using a high-frequency survey carried out between September 2012 and December 2019. It is based on beach profile measurements along two transects, modelling offshore wave data (WW3), tide gauge records, and shallow waves and water levels recorded in the intertidal zone. A barrier retreat of À23 to À30 m over the 7-year survey (i.e. À3.3 to À4.3 m yr À1 ) is measured. This retreat is not related to long-term sea level rise (macroscale of 10 2 -10 3 yr), but to mesoscale (10 0 -10 2 yr) morphogenic events combining storm wave and high spring tide. Over 87-90% of the barrier retreat is due to three significant events (1-2 February 2014, 9 February 2016, and 3 January 2018). The storm impact scale model of Orford and Carter is tested. The estimation of the wave runup for the calculation of extreme water levels [i.e. peak overflow elevation (O e ) component] is based on the calibration of an equation performed from in-situ measurements of the swash elevation. The flow depth (O d,q ) overtopping the crest of the barrier (B h ) is thresholded by taking into account the morphological response of the barrier in order to define regimes corresponding to overtopping, discrete overwash, and sluicing overwash. While the Orford and Carter model is generally successful in reproducing the morphodynamic evolution of Sillon de Talbert, the wave energy flux (F) must be considered as an additional parameter in order to improve the fit of the model, so far as it contributes in some cases to change the morphodynamic regime. Thus, the wave energy flux constitutes a key component in the quantification of the water flow across the barrier (O d,q ) corresponding to the hydrodynamic forcing of the model, which becomes (O d,F ).

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Section: Discussionmentioning

confidence: 99%

“…In our case, the largest bed roughness for gravel particles induces a flow retardation, which may also be increased by higher percolation, leading to a loss of swash volume. Both processes contribute to limit the runup, explaining that the porous structures are widely used as breakwaters for coastal defence (Guo et al, 2020;Twu & Chieu, 2000;Venkateswarlu & Karmakar, 2019). In addition, as proposed to distinguish the different regimes of Orford and Carter's storm impact scale model (Orford & Carter, 1982).…”

Section: Calibration Of Runup Formulamentioning

confidence: 99%

Catastrophic overwash and rapid retreat of a gravel barrier spit during storm events (Sillon de Talbert, North Brittany, France)

Suanez

Stéphan

Autret

et al. 2022

Earth Surf Processes Landf

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“…The trapping chamber regions are characterised by minimum wave reflection for a particular interval termed as resonating trough. 7 The resonating troughs are considered as an effective design points to attain minimal wave impact on breakwaters. Further, the studies are carried out for wave transformation due to barrier-rock porous structure placed on step-bottom and numerical investigation on the wave dissipation due to multiple porous structures is performed by Venkateswarlu and Karmakar.…”

Section: Introductionmentioning

confidence: 99%

“…Further, the studies are carried out for wave transformation due to barrier-rock porous structure placed on step-bottom and numerical investigation on the wave dissipation due to multiple porous structures is performed by Venkateswarlu and Karmakar. 7,8 The study related to vertical wall as a breakwater showed that the trapping chamber length plays an important role in the wave trapping and the resonating behaviour is evident due to the presence of the trapping chamber.…”

Section: Introductionmentioning

confidence: 99%

Wave trapping due to composite pile-rock structure coupled with vertical barrier

Sreebhadra

Krishna

Karmakar

2022

Proceedings of the Institution of Mechanical Engineers, Part M:

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The wave transformation due to pile-rock porous structure in combination with vertical porous barrier is studied under oblique wave action. The pile-rock breakwaters consists of two rows of closely spaced piles and a rock core between them is effective in dissipating wave energy when compared with traditional rigid breakwaters due to its reduced deadweight of construction materials and additional stability. Three different cases of the vertical barrier configurations such as fully-extended barrier, bottom-standing barrier and surface-piercing barrier placed in front of the pile-rock porous structure are considered for the investigation. The numerical study is performed using the eigenfunction expansion and the associated orthogonal mode-coupling relations considering the continuity of pressure and velocity for the vertical barrier, seaward and leeward structural interfaces. The Darcy’s law is incorporated for the flow through porous media and the porosity factor of the structure is introduced using the complex porous effect parameter. The numerical results for the wave reflection, transmission and dissipation coefficient, wave force on front and rear side of porous structure along with the wave force on the barrier interface are evaluated for different hydraulic characteristics. The analysis is presented for varying structural porosity, angle of incidence, structural thickness, friction factor, length between vertical barrier and porous structure for the three different cconfigurations of vertical barrier. The numerical investigation performed in the present study will be useful for the design and analysis of the composite breakwater system to protect the offshore facility from high waves.

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“…The study reported that the wave trapping not only depends upon barrier position but also on the porous effect parameter, 23 which plays an immense role in wave dissipation. Thereafter, porous structure placed on sloping seabed, 24 step-bottom, 25 submerged and surface piercing structure of finite width, 26 double porous barriers 27 and multiple structures away from leeward wall 28 is extensively analysed considering various incident wave and structural properties. The trapping chamber length encourages the resonating peaks and troughs in wave transformation, and resonating troughs are evident in the design of porous structure away from vertical wall to achieve maximal wave trapping.…”

Section: Introductionmentioning

confidence: 99%

Wave motion over stratified porous absorber combined with seaward vertical barrier

Venkateswarlu

Karmakar

2020

Proceedings of the Institution of Mechanical Engineers, Part M:

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The oblique wave reflection by horizontally stratified porous absorber having two horizontal porous bars of different porosities and friction factors placed on step-type bottom is studied using eigenfunction expansion method based on linearised wave theory. The present study examines several structural configurations such as porous absorber consisting of finite and semi-infinite thickness with/without seaward vertical barrier. The present study derived the direct analytical relations to determine wave reflection by each of the structural configuration for plane-wave assumption using potential flow theory. Initially, the porous absorber considering uniform porosity and friction factor is examined and validated with available numerical results, and the direct analytical relations are also validated with available relations of possible structural configurations. In addition, the present study reported wave reflection performance of submerged single-layer and double-layer porous absorbers with/without seaward vertical barrier. The effect of bottom rigid bar, surface porous bar, middle porous bar depth, multiple porosities, friction factors, incident wave angle and porous effect parameter on wave reflection coefficient is presented in detail for various structural configurations. The significance of seaward vertical barrier on wave reflection and wave trapping is reported. The point of wave trapping, critical angle of impinging, resonating peaks and troughs due to various structural configurations are presented against structural thickness.

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Numerical investigation on the wave dissipating performance due to multiple porous structures

Cited by 18 publications

References 44 publications

Catastrophic overwash and rapid retreat of a gravel barrier spit during storm events (Sillon de Talbert, North Brittany, France)

Catastrophic overwash and rapid retreat of a gravel barrier spit during storm events (Sillon de Talbert, North Brittany, France)

Wave trapping due to composite pile-rock structure coupled with vertical barrier

Wave motion over stratified porous absorber combined with seaward vertical barrier

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