The Exploitation And Properties Study Of Wave Dissipation In A Wave Tank

A wave tank is an important place to make experimental studies associated with waves.Wave dissipation device is an important equipment,which is used in a tank to eliminate wave energy and prevent wave reflection from influencing experimental results.Different wave dissipation devices have different effects on eliminating wave energy,and the wave elimination performances will directly affect the accuracy of experiments in tanks.Until now,the materials about all kinds of studies of wave dissipation devices in tanks are scarce.Therefore,it is necessary to develop a new wave dissipation device so as to provide more actual situation of working environment for wave experiment in tanks.Analyze and summarize the properties and principles of eliminating wave energy of some other wave dissipation structures carefully,mainly including five structures.They are wave dissipation of wire fabrics type,case type and circular type,multiple layer breakwater and perforated-pipe breakwater.And then develop a new device,which is named the variable diameter tilted perforated plates wave dissipation device.Although the variable diameter tilted perforated plates wave dissipation device is provided for wave dissipation of wave tanks,after its principles and basic structure are further developed,it can be used to protect seashore from wave erosion as a new type of penetrating breakwaters in the future.The model experiment about the variable diameter tilted perforated plates wave dissipation device was made in a wave tank.The tank belongs to ship and ocean engineering mechanics basic lab in the Harbin Engineering University.In the experiment,wave probes were placed at the device’s front-and-back to measure wave heights and periods.The waves in front of the device were separated with two points method to get reflection waves.Reflection,transmission and dissipation coefficients were calculated by using wave heights of reflection,transmission and incident waves.The experiment mainly includes that reflection,transmission and dissipation coefficients were effected by the change of spacing of perforated plates,titled angles,water depth,wave-length and wave-height.Analyze and study the merits and characteristics of wave dissipation properties of the variable diameter tilted perforated plates wave dissipation device compared with wave dissipation properties of other wave dissipation devices.The characteristic curves and data are given.The followed results are found through the study.The wave dissipation capacity of the variable diameter tilted perforated plates wave dissipation device decreases with the increasing of wave-length and increasing with the increasing of wave-height.Within the range of experiment,the less titled angle is and the deeper relative underwater depth is,the better the properties of the device are.Decreasing spacing of plates can better eliminate the energy of the waves whose wave-lengths are short and whose wave-heights are high.When it is placed at the end of a tank,the device has good effects of wave dissipation,and its reflection and dissipation coefficients are both bigger than the coefficients of the device which is placed in the middle of a tank.Compared with other wave dissipation structures,the variable diameter tilted perforated plates wave dissipation device has obvious advantages in the aspects of wave dissipation capacity and adaptability.