This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interac...This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interaction with the H-shaped breakwater is examined by analyzing the wave reflection,transmission,and dissipation coefficients.Additionally,the horizontal wave force coefficients are evaluated to analyze the effectiveness of the horizontal plates when integrated with the main structure.The primary structural parameters directly affect the performance of the composite breakwater and are varied within the feasible range of nondimensional wave numbers,relative spacings,and incident wave angles.This study presents a comparative analysis of the arrangement of the horizontal plates in terms of spacing and inclinations inward and outward to the breakwater using a multidomain boundary element method(BEM).The variation of the structural parameters proposes suitable dimensions for integrated H-shaped breakwater with horizontal plates that provide optimal performance in shallow and deep-water regions.The optimum plate porosity,dimensions of the H-shaped structure,inclinations,and spacing between the plate and breakwater are thoroughly discussed.This study shows that impermeable plates are the excellent means to control the wave force in the intermediate water depth regions than in deep-water regions at resisting wave force.The wave force coefficient on the breakwater is significantly larger than that on the seaside plates.Interestingly,inward-inclined plates perform most efficiently at angles greater than 5°,except in deep-water regions where horizontal plates perform better.In addition,this study noted that regardless of water depth,the outward-inclined plates are the least effective in reflecting the incident wave energy.This study will help plan the layout of suitable composite structures for efficient near-shore and offshore harbor protection according to the site criteria and environmental conditions.展开更多
The present study investigates the effect of moorings on hybrid floating breakwaters of different configurations based on potential flow theory.The mooring analysis is performed for the regular wave incidence for five...The present study investigates the effect of moorings on hybrid floating breakwaters of different configurations based on potential flow theory.The mooring analysis is performed for the regular wave incidence for five different shapes of hybrid floating breakwaters,namely,rectangular,box,H,Π,and trapezoidal,integrated with a single J-shaped oscillating water column(OWC).The mooring lines are considered to be nonlinear catenary sections that are analysed for open mooring and cross mooring configuration.The hydrodynamic analysis is performed using Ansys-AQWA and the effectiveness of the moorings is evaluated in terms of the mooring line tension and the floating structure’s motion response,and comparisons are made for the influence of different mooring configurations and the implications of changing the design of the hybrid floating breakwater.The regular gravity wave frequency range is taken into consideration and the hydrodynamic properties are reported for the entire range of regular wave frequencies.Additionally,for a few chosen wave frequencies the analysis of structural forces and moment is performed for long and short waves.The study suggests that a hydrodynamically stable hybrid floating structure integrated with an oscillating water column can provide good and effective wave energy conversion and wave attenuation.Thus,with the help of the findings of the present study,the researchers will be able to examine the stability of hybrid floating breakwater structures under the action of regular waves with normal incidence.展开更多
The wave interaction with stratified porous structure combined with a surface-piercing porous block in a stepped seabed is analysed based on the small amplitude wave theory.The study is performed to analyse the effect...The wave interaction with stratified porous structure combined with a surface-piercing porous block in a stepped seabed is analysed based on the small amplitude wave theory.The study is performed to analyse the effectiveness of partial porous structure in increasing the wave attenuation in the nearshore regions consisting of stratified porous structures of different configurations using the eigenfunction expansion method and orthogonal mode-coupling relation.The hydrodynamic characteristics such as wave reflection coefficient,transmission coefficient,dissipation coefficient,wave force impact and surface elevation are investigated due to the presence of both horizontally and vertically stratified porous structures.The effect of varying porosity,structural width,angle of incidence,wavelength and length between the porous block and stratified structure is examined.The numerical results are validated with the results available in the literature.The present study illustrates that the presence of the stratified structure decreases wave transmission and efficient wave attenuation can also be easily achieved.The wave force acting on stratified structure can be decreased if the structure is combined with wider surface-piercing porous blocks.Further,the presence of stratified porous structure combined with porous block helps in creating a tranquil zone in the leeside of the structure.The combination of vertical and horizontal stratified porous structure with surface-piercing porous block is intended to be an effective solution for the protection of coastal facilities.展开更多
The present research work concerns about the hydrodynamic behaviors of the open net offshore fish cages of single,double and 4-cage systems subjected to regular sinusoidal waves.The open net semisubmersible rigid cage...The present research work concerns about the hydrodynamic behaviors of the open net offshore fish cages of single,double and 4-cage systems subjected to regular sinusoidal waves.The open net semisubmersible rigid cage is square in shape and analyzed numerically using ANSYS AQWA software.Frequency and time domain analyses are carried out for each case.The hydrodynamic parameters such as added mass,radiation potential damping,motion responses and mooring line tensions are considered as performance indicators to conclude as the best arrangements among three different cages.The single cage and windward side of all cages exhibit identical performance in all hydrodynamic parameters.The leeward side of each cage shows lesser parametric values than the windward side cages.Based on the performance indicators,it is concluded that the grid system containing four cage arrangements provides better performance than three other cage configurations.An experimental model of 1∶75 scale is fabricated and wave flume studies are conducted to validate the present numerical model.The cage is placed at a water depth of 55 cm and subjected to wave heights of 12 cm and 14 cm with wave periods ranging from 0.8 s to 2.2 s with an interval of 0.2 s are considered.The same wave flume boundary conditions are adopted for numerical simulations and results are in good agreement with experimental work results.展开更多
The present paper presents the sloshing oscillation behaviour and sloshing force in three different tanks of model scales of 1:86,1:57 and 1:43.The rectangular tank is mounted on shake table,to study the scale effect ...The present paper presents the sloshing oscillation behaviour and sloshing force in three different tanks of model scales of 1:86,1:57 and 1:43.The rectangular tank is mounted on shake table,to study the scale effect of sloshing with sway excited motion.The tests are carried out for the aspect ratio(hs/l,where hs liquid depth and l is the length of the tank)of 0.1625,0.325,and 0.4875 which represents 25%,50%and 75%of liquid fill levels,respectively.Seventeen excitation frequencies ranging from 0.4566 Hz to 1.9757 Hz are considered,which covers up to the fifth sloshing mode.The sloshing oscillations occurs in the longitudinal axis when subjected to sway excitations.An experimental setup is designed and devised to measure sloshing force by the concept of ballast mass.The inertia forces are measured by load cells and sloshing oscillation time histories are measured by capacitance probes.It is found that violent sloshing is experienced for 50%filled condition irrespective of scaled tanks,excitation amplitudes and excitation frequencies.The sloshing force is maximum in 1:43 scaled tank than other scaled sloshing tanks irrespective of the excitation frequency and amplitude for 50%fill level.Based on the experimental observations and analysis of results,it is concluded that proportionate volume of water and tank size decides the severity of sloshing in the partially filled tanks.展开更多
The present study investigates the wave-damping characteristics due to the combination of bottom-standing porous structure,submerged porous plate,and fully-extended porous structure of finite width using the small amp...The present study investigates the wave-damping characteristics due to the combination of bottom-standing porous structure,submerged porous plate,and fully-extended porous structure of finite width using the small amplitude wave theory.The hydrodynamic characteristics such as reflection,transmission,and dissipation coefficients are determined to analyse the wave energy dissipation by the composite breakwater using the matched eigenfunction expansion method and orthogonal mode-coupling relation.Darcy’s law is incorporated to the flow through porous media.The composite breakwater system is investigated experimentally to validate and compare the numerical results with the physical model study.The complex porous effect parameter for the submerged plate is incorporated in the numerical analysis,which represents the reactance and resistance of the porous structure.The wave forces on the submerged plate and porous structure for the composite breakwater are investigated by considering the effects of changing parameters such as structural porosity,plate submergence,angle of incidence,width of the submerged porous structure and distance between the structures.The study illustrates that the increasing width of the fully-extended porous structure improves the performance of the breakwater system.The proposed study on the composite breakwater yields an useful information for wave energy attenuation,which can be designed and implemented in coastal and harbour areas to achieve wave tranquillity.展开更多
基金the partial support from the Ministry of Ports,Shipping and Waterways,Government of India,through the research grant no.DW/01013(13)/2/2021.
文摘This study analyzes the hydrodynamic performance of an H-shaped pile-restrained composite breakwater integrated with a pair of horizontal plates placed on the seaside and the leeside of the breakwater.The wave interaction with the H-shaped breakwater is examined by analyzing the wave reflection,transmission,and dissipation coefficients.Additionally,the horizontal wave force coefficients are evaluated to analyze the effectiveness of the horizontal plates when integrated with the main structure.The primary structural parameters directly affect the performance of the composite breakwater and are varied within the feasible range of nondimensional wave numbers,relative spacings,and incident wave angles.This study presents a comparative analysis of the arrangement of the horizontal plates in terms of spacing and inclinations inward and outward to the breakwater using a multidomain boundary element method(BEM).The variation of the structural parameters proposes suitable dimensions for integrated H-shaped breakwater with horizontal plates that provide optimal performance in shallow and deep-water regions.The optimum plate porosity,dimensions of the H-shaped structure,inclinations,and spacing between the plate and breakwater are thoroughly discussed.This study shows that impermeable plates are the excellent means to control the wave force in the intermediate water depth regions than in deep-water regions at resisting wave force.The wave force coefficient on the breakwater is significantly larger than that on the seaside plates.Interestingly,inward-inclined plates perform most efficiently at angles greater than 5°,except in deep-water regions where horizontal plates perform better.In addition,this study noted that regardless of water depth,the outward-inclined plates are the least effective in reflecting the incident wave energy.This study will help plan the layout of suitable composite structures for efficient near-shore and offshore harbor protection according to the site criteria and environmental conditions.
文摘The present study investigates the effect of moorings on hybrid floating breakwaters of different configurations based on potential flow theory.The mooring analysis is performed for the regular wave incidence for five different shapes of hybrid floating breakwaters,namely,rectangular,box,H,Π,and trapezoidal,integrated with a single J-shaped oscillating water column(OWC).The mooring lines are considered to be nonlinear catenary sections that are analysed for open mooring and cross mooring configuration.The hydrodynamic analysis is performed using Ansys-AQWA and the effectiveness of the moorings is evaluated in terms of the mooring line tension and the floating structure’s motion response,and comparisons are made for the influence of different mooring configurations and the implications of changing the design of the hybrid floating breakwater.The regular gravity wave frequency range is taken into consideration and the hydrodynamic properties are reported for the entire range of regular wave frequencies.Additionally,for a few chosen wave frequencies the analysis of structural forces and moment is performed for long and short waves.The study suggests that a hydrodynamically stable hybrid floating structure integrated with an oscillating water column can provide good and effective wave energy conversion and wave attenuation.Thus,with the help of the findings of the present study,the researchers will be able to examine the stability of hybrid floating breakwater structures under the action of regular waves with normal incidence.
基金Science and Engineering Research Board(SERB),Department of Science&Technology(DST),Government of India for supporting financially under the research grant No.CRG/2018/004184Ministry of Ports,Shipping and Waterways,Government of India through the research grant No.DW/01013(13)/2/2021.
文摘The wave interaction with stratified porous structure combined with a surface-piercing porous block in a stepped seabed is analysed based on the small amplitude wave theory.The study is performed to analyse the effectiveness of partial porous structure in increasing the wave attenuation in the nearshore regions consisting of stratified porous structures of different configurations using the eigenfunction expansion method and orthogonal mode-coupling relation.The hydrodynamic characteristics such as wave reflection coefficient,transmission coefficient,dissipation coefficient,wave force impact and surface elevation are investigated due to the presence of both horizontally and vertically stratified porous structures.The effect of varying porosity,structural width,angle of incidence,wavelength and length between the porous block and stratified structure is examined.The numerical results are validated with the results available in the literature.The present study illustrates that the presence of the stratified structure decreases wave transmission and efficient wave attenuation can also be easily achieved.The wave force acting on stratified structure can be decreased if the structure is combined with wider surface-piercing porous blocks.Further,the presence of stratified porous structure combined with porous block helps in creating a tranquil zone in the leeside of the structure.The combination of vertical and horizontal stratified porous structure with surface-piercing porous block is intended to be an effective solution for the protection of coastal facilities.
文摘The present research work concerns about the hydrodynamic behaviors of the open net offshore fish cages of single,double and 4-cage systems subjected to regular sinusoidal waves.The open net semisubmersible rigid cage is square in shape and analyzed numerically using ANSYS AQWA software.Frequency and time domain analyses are carried out for each case.The hydrodynamic parameters such as added mass,radiation potential damping,motion responses and mooring line tensions are considered as performance indicators to conclude as the best arrangements among three different cages.The single cage and windward side of all cages exhibit identical performance in all hydrodynamic parameters.The leeward side of each cage shows lesser parametric values than the windward side cages.Based on the performance indicators,it is concluded that the grid system containing four cage arrangements provides better performance than three other cage configurations.An experimental model of 1∶75 scale is fabricated and wave flume studies are conducted to validate the present numerical model.The cage is placed at a water depth of 55 cm and subjected to wave heights of 12 cm and 14 cm with wave periods ranging from 0.8 s to 2.2 s with an interval of 0.2 s are considered.The same wave flume boundary conditions are adopted for numerical simulations and results are in good agreement with experimental work results.
基金The Science and Engineering Research Board(SERB)and Department of Science and Technology(DST),Government of India under the project“Optimal Damping of Porous Screen in TLDStructure Interaction”(ECR/2015/000176).
文摘The present paper presents the sloshing oscillation behaviour and sloshing force in three different tanks of model scales of 1:86,1:57 and 1:43.The rectangular tank is mounted on shake table,to study the scale effect of sloshing with sway excited motion.The tests are carried out for the aspect ratio(hs/l,where hs liquid depth and l is the length of the tank)of 0.1625,0.325,and 0.4875 which represents 25%,50%and 75%of liquid fill levels,respectively.Seventeen excitation frequencies ranging from 0.4566 Hz to 1.9757 Hz are considered,which covers up to the fifth sloshing mode.The sloshing oscillations occurs in the longitudinal axis when subjected to sway excitations.An experimental setup is designed and devised to measure sloshing force by the concept of ballast mass.The inertia forces are measured by load cells and sloshing oscillation time histories are measured by capacitance probes.It is found that violent sloshing is experienced for 50%filled condition irrespective of scaled tanks,excitation amplitudes and excitation frequencies.The sloshing force is maximum in 1:43 scaled tank than other scaled sloshing tanks irrespective of the excitation frequency and amplitude for 50%fill level.Based on the experimental observations and analysis of results,it is concluded that proportionate volume of water and tank size decides the severity of sloshing in the partially filled tanks.
基金The authors acknowledge Science and Engineering Research Board(SERB),Department of Science&Technology(DST),Government of India for supporting financially under the research Grant No.CRG/2018/004184Ministry of Ports,Shipping and Waterways,Government of India through the research Grant No.DW/01013(13)/2/2021.
文摘The present study investigates the wave-damping characteristics due to the combination of bottom-standing porous structure,submerged porous plate,and fully-extended porous structure of finite width using the small amplitude wave theory.The hydrodynamic characteristics such as reflection,transmission,and dissipation coefficients are determined to analyse the wave energy dissipation by the composite breakwater using the matched eigenfunction expansion method and orthogonal mode-coupling relation.Darcy’s law is incorporated to the flow through porous media.The composite breakwater system is investigated experimentally to validate and compare the numerical results with the physical model study.The complex porous effect parameter for the submerged plate is incorporated in the numerical analysis,which represents the reactance and resistance of the porous structure.The wave forces on the submerged plate and porous structure for the composite breakwater are investigated by considering the effects of changing parameters such as structural porosity,plate submergence,angle of incidence,width of the submerged porous structure and distance between the structures.The study illustrates that the increasing width of the fully-extended porous structure improves the performance of the breakwater system.The proposed study on the composite breakwater yields an useful information for wave energy attenuation,which can be designed and implemented in coastal and harbour areas to achieve wave tranquillity.
