研究了感潮河网的水环境容量。研究表明影响感潮河网水环境容量的主要因素为: 潮汐作用、调蓄库容、水利工程的调控运行、污染物的降解系数和边界引水水质。基于感潮河网水质模型, 完善了其水环境容量的计算方法。以上海市浦南东片河网为例,分析了感潮河网水环境容量在上述因素影响下的时空变化规律,并提出了相应条件下的污染物日允许排放量。

The vertical turbulent mixing of the isodensity oscillation current in tide estuary has been studied in this paper, On the basis of the governing equation and character analysis of the tidal flow, the expression of time-space distribution of shear stress, which is influenced by gravity and inertia, has been derived. Considering the terms of gravity and inertia, the theoretical equation of turbulent exchange coefficient of the tide estuary flow has been developed. Then the vertical average and the time average equation have also been obtained .To verify those equations, the time-space distribution of vertical turbulent exchange coefficient in Yangtze Estuary has been calculated according to measure data. Its variation character with the flood and ebb tide has been analyzed.

Unsteady Water quality model with multiparameter for the river network has been studied in this paper. The model reflects the characteristics of the unsteady flow with different direction and that of the unsteady water quality under aerobic, anoxic and anaerobic conditions. The model includes the various equations for DO, COD, BOD5, NBOD, NH4+-N.All parameters in the model have been obtained by the research for the observation on the field and the experiment in the laboratory. An equation of longitudinal dispersion coefficient has also been developed. Appling the computing method of dynamic coupling, the model has been verified by the data observed on field. The model has been applied to the program for controlling water quantity and water quality in order to improve the water quality of the river network of Wuxi city in China.

The thixotropy properties and the motion law of a sphere in the Bingham fluid have studied. Through observation of the setting motion of a single sphere in the Bingham fluid on the X-ray screen, it has been discovered that the mud in estuaries and along sea bay, and the hyperconcentrated flow all behave as the Bingham fluid with thixotropy properties as the large sediment concentration. Through derivation, the theoretical relationship between the yield stress and non-setting maximum sphere supported by the stress for the Bingham fluid has been developed, the equations for calculating the increasing yield stress and the non-setting maximum sphere diameter with the duration at rest of the slurry have been obstained. In consideration of the effect thixotropy on the fluid motion. The Navier-Stokes equation group for the Bingham thixotropy fluid has been developed. Through future study of the flow boundary condition of setting motion of a single sphere in the Bingham thixotropy fluid. And the solving of the Navier-Stokes equation group under the small Reynolds number. The theorecital equation of the drag force of the Bingham thixotropy fluid flowing around a sphere has been deduced. The theorecital relationship between drag coefficient and Revnolds number has been derived. By use of the experimental data of rheological test of various slurries measured with viscometer and those of single sohere motion observed on the X-ray screen, the above equation have been verified. The equations are in good agreement with the experimental data for various slurries.

It has been discovered through experiment that the slurries at Huayuankou on the Yellow River, Lianyuangang, Dmgang, Yangtze River estuary, Dunkerque of France, etc. all behave as the Bingham fluid with thixotropic properties as the sediment concentration is large. Consequently, the setting velocity of a sphere, the maximum diameter of non-setting sphere and the shear stress of incipient motion of cohesive sediment in the slurry change significantly with the duration of rest after the slurry is strongly agitated, Based on the above fact, the quantitative relationship between the shear stress of incipient motion of cohesive sediment and the factors of the sediment concentration, the particle size, the yield stress measured by the viscometer and the duration of rest after agitation(consolidation time), etc, has been developed, and good results have been obtained, The condition of incipient motion of non-cohesive sediment obtained by various investigators have also been transformed to the dimensionless critical shear stress θ. It is found that the various values of θ, in general, come between Einstein’s 0.0715 and Shamofu’s (Шамов) 0.0245.