Enhancement Of The Performance Of Traditional Wave Absorber In The Laboratory

The laboratory wave tank is a place where we make experimental studies associated with wave test.The wave dissipation facility is an important device that placed at the end of the tank to sbsorb wave energy and mitigate the reflection wave from interfering with the accuracy of the experiment.With the further development of the ocean engineering,experimental research has also attracted more and more attention.The accuracy and reliability of experimental data are even more urgent.Therefore,a wave-absorption facility that can effectively absorb wave energy in experimental tanks is important to the researchers.Most of the traditional wave absorption facilities are lithotripsy slope structures.Although this structure has good wave absorption performance in a certain range of wave periods,there are many shortcomings,especially for the large length of the tank.In the shorter tank,the energy dissipation problem of the gravel slope structure is also large.Most of the traditional wave absorbing facilities are gravel slope structures.Although this structure has good wave absorbing performance in a certain range of wave cycles,there are many shortcomings,which account for the large length of the tank.In the shorter tank,the energy dissipation problem of the gravel slope structure is also large.Traditional wave dissipation facilities can be divided into vertical,inclined and curved slopes according to geometry shapes.The wave dissipation facility for different materials have different wave absorbing effects,such as concrete blocks,crushed stones,synthetic fibers,foam and metal mesh etc.The sponge is a special kind of foam material.Different sponge has great difference in wave dissipation effect.Polyurethane foam has certain water permeability and water absorption ability,and can be used as a material for making wave dissipation device.Combining the structural characteristics and foam characteristics of traditional wave dissipation facilities,three kinds of wave absorption devices are proposed,which are composed of sponges and crushed stones as internal structural materials.They are the upper tilted lower vertical mixed structure wave absorption device,the upper part of the parabolic vertical mixed structure wave absorption device and the stone spongy mixed slope structure,and the two dimensional model is carried out in the wave flume respectively.In order to judge the wave dissipation effect of each experimental device,the two-point method is used to calculate the reflection coefficient and transmission coefficient.By comparing with the effect of wave dissipation of the gravel slope structure,it is proved that the three kinds of devices have a certain wave absorping ability and have good wave absorption effect in a certain wave period range.The test content also includes the influence of water depth,wave height and periodic change on the wave dissipation capacity of different devices,and combined with data,the factors of wave absorping ability of the device are analyzed in depth,and the wave absorption ability of their respective devices under the conditions of different wave elements is discussed.It was also found that the wave dissipation effect decreased significantly with the increase of the incident wave period,and the wave dissipation effect increased slightly with the increase of water depth.When the wave period is in 0.8~1.8s,the wave absorpting performance of the three kinds of wave absorption devices is better.In the period of more than 2s,the effect of wave absorption is very different.The stone-sponge mixed slope structure is better than the other two kinds of devices.Finally,the advantages and disadvantages of the three wave absorbing devices and the gravel slope structure are summarized and analyzed,and the improvement suggestions are given.