Study On The High Accuracy Scheme To Simulate Water Temperature Of River

Follow the developments of social economy, the problem of water environment has risen the attention of the world. As a basic work to solve the problem of water environment, the water environment evaluation and prediction is a significant work to protect the water environment. Water temperature is an essential element in the evaluation of the hydrologic environment, so exact prediction of water temperature is the basis of many water quality models. And the key step to predict water temperature exactly is to create a math quantitative model and find the numerical solution which can image the real physical process. The apply of the high accuracy scheme which can model the real physical process accurately has some advantages in modeling and predicting the transfer of water temperature. On the basis of what forefathers studied, this context derived a new high accuracy scheme to simulate convection-diffusion equation by using the undetermined coefficient method, and then applied the new scheme to create the 1-D, 2-D water temperature forecasting model.There are four chapters in this paper:First there is an exordium. The survey of numerical computation development and its main method were exposited, and the developments of domestic and overseas numerical simulation for convection-diffusion equations and the 1-D, 2-D water temperature prediction model were also systematically summarized. Combined with the inclination of international CM) academe's demand for the numerical scheme, this chapter pointed that the numerical simulation technology with high accuracy scheme has already become the important research trend of the present river numerical simulation technology.By using the undetermined coefficient method, Chapter 1 created HAUC2 scheme to simulate the 1-D. 2-D convection-diffusion equations. Conservative form of this new scheme was also presented. Numerical test showed that this new scheme was well suitable for both convection-dominant flow and diffusion- dominant flow and could be used to predict the convection-diffusion of pollution.Chapter 2 adopted the 4-points eccentric Preissmann scheme and HAUC2 scheme to disperse flow governing equation and heat transportation equation separately, and found 1-D non-conjunction model for unsteady flow and water temperature. Then the model wasused to simulale the convection and diffusion of water temperature in Huangzhuang to Xiantao reach of L-lanjiang River , the and the results proved that the model created in this chapter could be put into practice.Chapter 3 applied finite volume method and used first order upwind scheme and HAUC2 scheme to disperse 2-D flow governing equation and heat transportation equation, and created depth-averaged 2-D non-conjunction model for unsteady flow and water temperature. The results from numerical experiment of generalized watercourse proved that the model can preferably simulate flow in watercourse and reflect the base law of temperature transportation, recur the true physical process, and it could be put into practice.Finally, Chapter 4 sums up the whole paper and prospects further research wprk in future.