Research On Reoxygenation Behavior Characteristics Of Wave

The dissolved oxygen is an important index of water quality, and atmosphere isone of the important sources of dissolved oxygen in water. In order to study theundersaturated dissolved oxygen behavior characteristics of wave and illustrate theinfluence of wave height, wave period, velocity and water depth, an oxygen masstransfer experiment of wave was established to measure the wave parameters,including wave height, wave period, velocity and dissolved oxygen concentrationfirstly. Secondly, base on the experiment data of regular and non-breaking wave, theoxygen mass transfer theory of water-gas interface, the mass conservation law and thedimensional analysis method were adopted to study the oxygen mass transfer. Anoxygen mass transfer coefficient equation is proposed, which considers wave kineticenergy, oxygen deficit and wave period. Thirdly, base on Fluent software, the sourcesin the momentum equation are used to generate and absorb waves, and the2-Dnumerical wave flume is established to generate and absorb waves. Fourthly, a2-Dmathematical model of dissolved oxygen transport and diffusion of wave is employedto compute the undersaturated dissolved oxygen, and it is validated by theexperimental data. The influence law of the initial dissolved oxygen concentration,wave height, wave period and velocity on the dissolved oxygen concentrationrecovery is analyzed. Finally, the dissolved oxygen transport and diffusion in largescale wave is calculated, and the water depth on the dissolved oxygen concentration isanalyzed.The results show when the wave parameters are the same respectively, the morethe difference between initial dissolved oxygen concentration and saturation dissolvedoxygen concentration is, the more the dissolved oxygen concentration increases. When the wave period and the initial dissolved oxygen concentration are the samerespectively, the more the wave height is, the more the increment of dissolved oxygenconcentration is. But the increment of dissolved oxygen concentration has a nonlinearrelationship with the wave height. Under the same initial dissolved oxygenconcentration and the same wave height respectively, the less the wave period is, themore the increment of dissolved oxygen concentration is. The influence of waveperiod on the dissolved oxygen concentration is much more than that of wave height.Under the circumstance of wave and current, the more the average velocity is, themore the increment of dissolved oxygen concentration is, and the wave and currentefficiency of reoxygenation is better than that of regular and non-breaking wave.The computational result of dissolved oxygen concentration in large scale waveindicates the dissolved oxygen concentration decreases with the increase of waterdepth. The dissolved oxygen concentration appears the stratification phenomenonfrom bottom to surface of the wave. The average dissolved oxygen concentration ofvertical line reaches the minimum at wave crest section, and reaches the maximum atwave trough section.