复式断面横流紊动水平射流特性试验

Experimental study of the behavior of horizontal turbulent jets in cross compound sections

为了揭示复式断面横流环境中三维圆形水平射流的特性,运用Micro ADV测速系统对射流流速比为12的横流紊动射流进行了实验研究,给出了射流典型横断面二次流速度的矢量图和主流速等值线图.实测速度场资料分析表明:在射流出口附近射流表现出强烈掺混和卷吸现象,主槽和边滩的衔接段存在着较强的二次流,同时射流与来流的相互作用表现出明显的分叉现象,其分叉半角为7.6°;复式断面产生的二次流有助于加速射流的分叉.实测的流动典型横断面紊动强度分布和湍动能等值线表明,射流在其核心区具有强烈紊动,且在整个流场中是各向异性的.最后给出了射流出口高度水平面的时均流速分布图.

3-D Micro acoustic Doppler velocity （ADV） was used to test the round jets in cross flow in unsymmetrical compound channel. The ratio of jet exit velocity to the environment velocity was 12. Typical cross sections of the flow field were studied by the secondary current velocity vector graph and contour of stream wise velocity. The measured velocity fields of the typical cross section show that there are strong mixture and entrainment phenomena near the jet orifice. The secondary current lies in the conjugation site of the main channel and the floodplain. There are bifurcation phenomena due to the interaction of the jets and cross flow with the half angel of the bifurcation 7.6°, which is enlarged by the secondary current. The turbulent kinetic energy and turbulent intensity in the typical cross section obtained by ADV shows that the jets is anisotropic one in the whole flow. The data can be used to identify the turbulent model and numerical methods.