Two-stroke outboard boat engines using total loss lubrication deposit a significant proportion ofudtheir lubricant and fuel directly into the water. The purpose of this work is to document the velocity and concentration field characteristics of a submerged swirling water jet emanating from a propeller in order to provide information on its fundamental characteristics. The properties of the jet were examined far enough downstream to be relevant to the eventual modelling of the mixingudproblem. Measurements of the velocity and concentration field were performed in a turbulent jet generated by a model boat propeller (0.02 m diameter) operating at 1500 rpm and 3000 rpm in a weak co-flow of 0.04 m/s. The measurements were carried out in the Zone of Established Flow up to 50 propeller diameters downstream of the propeller, which was placed in a glass-walled flumeud0.4 m wide with a free surface depth of 0.15 m. The jet and scalar plume development were compared to that of a classical free round jet. Further, results pertaining to radial distribution, self similarity, standard deviation growth, maximum value decay and integral fluxes of velocity and concentration were presented and fitted with empirical correlations. Furthermore, propeller induced mixing and pollutant source concentration from a two-stroke engine were estimated.
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机译：使用全损润滑的二冲程舷外船用发动机将很大一部分润滑剂和燃料直接沉积到水中。这项工作的目的是记录螺旋桨发出的浸入水中的旋涡水射流的速度和浓度场特征，以便提供有关其基本特征的信息。对射流的特性进行了足够远的下游检查，以与最终的混合/问题建模相关。速度和浓度场的测量是在模型船螺旋桨（直径0.02 m）以1500 rpm和3000 rpm的弱共流0.04 m / s产生的湍流中进行的。测量是在螺旋桨下游最多50个螺旋桨直径的既定流量区域中进行的，将其放置在宽达ud0.4 m的玻璃墙水槽中，自由表面深度为0.15 m。将射流和标量羽状流的发展与经典的自由圆射流进行了比较。此外，提出了与径向分布，自相似性，标准偏差增长，最大值衰减以及速度和浓度的积分通量有关的结果，并与经验相关。此外，还估算了二冲程发动机的螺旋桨引起的混合和污染物源浓度。
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