水面舰船尾流电导率信号分布规律的研究

Conductivity Signal Distribution Law for Surface Ship Wake

在舰船尾流区与非尾流区之间存在显著的速度差和盐度(或密度)差,利用电导率探头可获得对应于这些差别的尾流电导率信号。在水槽中形成了与海洋环境类似的盐度分层流场,由双螺旋桨自航水面船模产生尾流,分别在盐度分层流场和非分层均匀流场中测量了尾流电导率信号的横向分布,并对盐度分层流场中水面舰船尾流的纵向速度分布进行了数值计算。结果表明:在盐度分层流场和非分层均匀流场中水面舰船尾流的电导率信号沿其横向近似呈高斯分布;尾流速度对其电导率信号的影响比盐度梯度的影响大得多;尾流的无量纲纵向速度亏损的数值计算结果与尾流的相对电导率信号横向分布的实测结果具有很好的一致性。

Velocity and salinity (or density) differences between the wake area and non-wake area of a surface ship may be measured with an electric conductivity probe. A salinity-stratified fluid field similar to the ocean environment, is simulated in a water tank, and the wake is resulted from a self-propelled, dual-propeller surface ship model. The lateral distributions of the conductivity signal of the wake are investigated respectively in the salinity-stratified fluid and a non-stratification homogeneous fluid and a numerical evaluation is carried out for the longitudinal velocity distribution of the surface ship wake in the salinity-stratified fluid. The results indicate that the wake conductivity signals obey approximately Gaussian Distributions along the lateral direction in both salinity-stratified fluid and the non-stratification homogeneous fluid, the effect of the wake velocity on the conductivity signal is much greater than that of the salinity gradient. The nondimensional longitudinal velocity loss of the wake coincides with the measurement of the lateral distribution of the relative wake conductivity signal very well.