射流掺气对水垫塘及坑底压强影响的实验研究

Influence of water ject aeration on pressure in scour pool and plunge pool

通过对射流掺气与不掺气时,水垫塘底板及冲坑底部脉动压强的对比试验,研究了掺气对水垫塘及冲坑底部压强特性的影响。结果表明:在冲坑未形成前,掺气使水垫塘底板上射流冲击区的脉动压强增加;无论是否掺气,滞点时均压强的量纲一分布遵从相同的规律,底板量纲一时均压强分布存在很好的自模性,且与气体冲击射流的压强分布具有相同的规律。冲坑形成后,掺气不再明显增大冲坑底部的脉动压强,掺气后,坑底脉动压强没有明显的变化。

The experiments are conducted about the influence of the aeration on dynamic pressure on riverbed before the scour hole formed is formed. Results show that the aeration enlarges the dynamic pressure on the riverbed bottom in the jet impact field before the formation of the scour hole. However the dimensionless mean pressure distribution at jet stagnant, the dimen- sionless mean pressure distribution on riverbed and the dimensionless ultimate dynamic pressure distrbution of the non-aerated flow and the aerated flow obey same rules. The dynamic pressure on the scour hole bottom is studied by means of the experi- ments, and the dynamic pressure characteristic during the scour process in the jet impact field is obtained, which indicates that the influence of the aeration on the dynamic pressure on bottom of scour hole is not obvious, and the root mean square of dynamic pressure distribution of the aerated jet on the bottom has no certain disciplinarian compared with the distribution of the non-aerated pure water jet.