| The field data of discharge and water stage during extreme events are important for flooding control and forecast.Firstly,the dam experiments and SPH facade two-dimensional numerical model was used to study the unsteady flow propagation characteristics.Then,shallow-water Smooth Participle Hydrodynamics(SPH)method was optimized and conducted to understand the characteristics of unsteady flow in open channel.The model was verified by the previous experimental results.It turned out that the precision of this algorithm is satisfying.Lag effect and the noose curve can be well simulated by it.Finally,the influence of external environment factors and the motion characteristics of unsteady flow in unsteadiness,lag effect and noose curve was researched by example calculation when only one variable was changed.The results show that,unsteadiness is positive correlation to the channel slop,but negative correlation to the roughness and inflow.The relationship between the unsteadiness and the rising/falling time presents a monotonically increasing power function.It is sensitive to the roughness,channel slop and inflow,but insensitive to channel width,the rising/falling time and fluid waveform.Lag effect has no obvious relation with the unsteadiness,but is sensitivity to inflow fluid waveform.Water level difference of water rising and down in the same cross section flow is a positive correlation with unsteadiness.Inflow waveform is very similar to noose curve after it was compressed properly and clockwise rotation.This conclusion can provide fluid of constancy strength considerations,hydrological calculation for reference.It shows that shallow-water Smooth Participle Hydrodynamics is applicable to mechanism study of fluid motion with high scientific research and engineering application promotion value. |
