基于表面设计减阻的水下航行体模型实验与数值分析

Experimental Study and Numerical Simulation on Drag Reduction of the Underwater Vehicle Based on Surface Profile Design

针对水下航行体高速航行时提高航速的需要,开展近壁面湍流边界层减阻的研究。进行表面设计使旋涡流动加强导致局部空化从而产生壁面附着的微气泡,以降低流体粘性系数,伴随近壁面湍流结构的改变来实现一定幅度的减阻。设计并进行轴对称体模型在高压循环水洞中的空化现象观测和阻力测量并做了相应条件下的数值计算。。实验和数值结果分析的基本结论比较一致:某种特征表面形貌在湍流中有一定幅度的减阻,局部空化效应在中低流速下牺牲压差阻力而导致航行总阻力升高,在高流速条件下则降低总阻力。

The experiment studies on near-wall turbulent drag reduction have been conducted for increasing speed of underwater vehicle. The latest conception on this subject is to reduce viscous coefficients, to interrupt the near-wall boundary turbulent behavior or to combine the two ways together. It is desirable to produce steady micro-bubble in the designed surface profile with which can limit turbulent flow and vortex converter across the streamline. The model test is designed and made for observing the cavitations and total force of an axis symmetric body in high-pressure circular water tunnel, which include rectangular, triangle and spline curve surface profiles. The test data is compared with the corresponding numerical simulation results. The later has the similar surface profile but the simplified computation domain with the boundary condition for computation convenience. It is concluded that the local cavitations effect forms negative pressure grads of the turbulent boundary therefore enforces total force under low and modest velocity but reduces the total force under high velocity.