波浪作用下双孔射流压强特性试验研究

Pressure Characteristics of Dual Jets under Wave Action

管道污水向海排放是一种典型的射流运动形式。在射流前行的过程中,波浪所引起的水体往复运动明显制约了射流的形成与发展,射流与波浪的相互作用的研究相对较少。利用数字压力传感器对波浪作用下双孔射流进行物理模型试验研究,分析波浪作用下双孔射流横断面压强分布及轴线衰减规律。试验结果表明:波浪条件下双孔射流横断面压强分布规律与静水条件相似,但是波浪条件下的射流压强大于静水条件下的射流压强,波周期越大,压强峰值增加越大;双孔射流的发展经历了单孔主导、双孔射流间的吸附和混掺、合并等过程;单孔主导区,射流压强分布与静水条件相似;吸附和掺混区,各孔衰减呈现出差异,第1孔与单孔射流类似,第2孔压强衰减较第1孔小,合并区双孔射流已为一股射流,其水动力特性与单孔射流类似;波浪对双孔射流的混掺合并有促进影响,随着周期的增大这种促进作用有增强的趋势,波周期的增大也使得射流合并断面提早出现。表明波周期对射流压强特性有显著影响。

Disposal of sewage into the oceans is a typical jet movement. As jet flows,the reciprocal motion of water generated by waves obviously restricts the formation and development of jet. However,less research has been done to study the interaction between jet and waves. In this article,physical model test of dual jets under wave action is conducted by using digital pressure sensor to analyze the pressure distribution and axial attenuation law of dual jet cross-section under wave action. The experimental results show that the pressure distribution of dual jets cross-section under wave condition is similar to that in hydrostatic condition,but the jet pressure under wave condition is larger than that under hydrostatic condition; the larger the wave period is,the greater the pressure peak value increases. The development of the dual jets has undergone single-hole-dominated,double-hole jet adsorption and blending,as well as merging processes. In the single-hole-dominated zone,the distribution of jet pressure is similar to that in hydrostatic condition; in the adsorption and blending zone,pressure attenuation in the holes varies,namely,pressure attenuation in the first hole is similar to that of single-hole jet,and the second hole smaller than that of the first hole; in the merging zone,the dual jets merge into one,with the hydrodynamic characteristics similar to that of a single-hole jet. Moreover,wave has a positive effect on the blending of dual jets,and the effect intensifies with the elongation of wave period,which also makes the jet merge section appear earlier,indicating that wave period has a significant influence on jet pressure.