射流冲沙研究

作者通过实验和分析，研究了横流中加入平面冲击射流对防止局部泥沙淤积的影响。水槽实验中观测了水射流局部紊动强度变化、射流冲沙范围内局部紊动剪应力分布、泥沙不淤积临界断面的底部垂向紊动强度和射流强度与泥沙防淤尺度的关系。得出了射流影响区水流紊动能随距离的衰减规律和保持泥沙不淤积所需的水流临界紊动强度。统计分析了射流强度与紊动能的变化关系。根据泥沙悬浮理论和射流紊动输沙机理，建立了水射流局部无泥沙淤积长度经验计算式，并以不同特性泥沙的射流输沙实验资料对所建立的计算公式进行了验证，二者吻合良好。

Experimental study on sediment transportation by impinging jet

The effect of plane impinging jet added into cross flow on preventing local silting was experimentally studied. Turbulence characteristics including turbulent intensity variation, distribution of turbulent shear stress on riverbed, the vertical turbulence intensity at the non-silting critical section and relationship between impinging intensity and non-silting range were measured. It was fount that the extent of non-silting expands as the jet velocity increases and the turbulent kinetic energy generated by the jet decreases as the distance from the impinging point increases. The vertical turbulence supports the suspension of sediment. According to the experiment data the variation of turbulent kinetic energy changing with jet velocity was analyzed. A formula for calculating the length of non-silting range was proposed.