A Study On Hydraulic Properties Of Groyne

River navigation is one of the important ways in transportation system. It has great potential of river navigation in our country. It is an urgent need for west development to use this precious resource fully and to promote river navigation.Groyne is a common measure used in channel improvement. It will give rise to serious consequence if the design of groyne is improper. To go deep into study of the variation of flow feature in river due to building groyne is extremely necessary. At present, physical model is mostly used way in research on river navigation and design of channel improvement. The approach of physical model will take longer time and charge more money although it will give us some direct impression. Because of the restriction by mode scale, velocity measuring is quite difficult. Especially the flow feature is difficult to describe accurately. Besides, traditional hydraulic method is commonly adopted to water surface computation in which section-averaged hydraulic parameters are used. The accuracy is quite low. It is backward comparing with modern computational fluid mechanics. Having the aid of newest achievement on computational fluid mechanic and computer simulation, to promote the study of river navigation hydraulics going to a new step has important academic significance and widely applied value. The work in the thesis is studied combining with the research project-key scientific and technical project on west China transportation of the period "Tenth Five".The content of this study has mainly two aspects: experimental study and mathematical modeling. The Laser-Doppler velometer is used to measure velocities. The flow conditions include submerged and non-submerged groynes. Experimental study includes the law of flow field variation and variation of water surface in affected zone by the single groyne or twin-groyne. Mathematical modeling includes following the trail of water surface in 2-D and 3-D conditions, model developing, verifying and applying ofthe model as well.Through the study above, a refined description and modeling to flow field and water surface near the groyne in river is conducted with 2-D and 3-D mathematical models. The results by simulation are consistent well with experiment data. The effect of groyne length and layout on water surface is analyzed in the paper. Based on the results of simulation and experiment, the local energy loss of the flow due to the groyne is studied. Consequently the surface variation and height of damming are also analyzed.Main creative points of the thesis are as following:1. It is the first time to apply 2-D and 3-D turbulent model of the air-water two phases flow to the study on hydraulic properties of groyne. It makes description of the turbulent flow field to be possible precisely. This offers a more accurate method to determine the water surface in channel improvement.2. Based on the results of experiment and simulation for 3-D turbulent model of air-water two phases flow, a new formula to compute the height of damming is built.3. Based on the 2-D mode and the formula to compute the height of damming, the subdivision method of 2-D computation for water surface at upstream and downstream.