扩散方程边界条件及恢复饱和系数

Boundary condition of diffusion equation and coefficient of saturation recovery

依据泥沙交换的统计理论,建立了非均匀沙扩散方程在床面的边界条件,它对一维、二维以至三维方程都是必须的,它将决定泥沙的冲淤.在此基础上积分二维扩散方程,得到了恢复饱和系数,阐述了它的特性,进而导出了在强平衡条件下的恢复饱和系数的理论表达式和相应的数字结果.最后给出了不平衡条件下恢复饱和系数的近似值和综合恢复饱和系数的数值.

The boundary condition at bed surface of diffusion equation of nonuniform sediment is derived based on the author＇ s concept of exchange intensity of stochastic theory. This condition is suitable for all 1-D,2-D,and 3-D equations,and determines the deposition and erosion. Integrating the 2-D diffusion equation, the coefficient of saturation recovery is derived and its characteristics can be revealed clearly. Then the theoretical expression of coefficient of saturation recovery under the strong equilibrium condition and the corresponding calculating value have been obtained. Finally, the approximate value of coefficient of saturation recovery under nonequibrium condition and the corresponding composite coefficient have also been presented.