水下航行体微气泡减阻特性试验研究

To study the effect laws of microbubble flow on drag reduction of an underwater vehicle and analyze morphological variation characteristics of microbubble flow, water tunnel tests were conducted for microbubble drag reduction features of an underwater vehicle based on a high speed camera system and a six-component force-measuring system. The morphologic variation characteristics of microbubble flow and its size distribution features were contrastively analyzed based on images captured by the high speed camera. The microbubble drag reduction characteristics and effects of microbubble size on drag reduction efficiency were analyzed based on the six-component force-measuring system. The test results showed that the main difference between microbubble flow morphology of ventilation ring model and that of ventilation section one under different ventilation rates is whether or not there are roll-up and cavity phenomena, and different microbubble flow morphologies directly affect the microbubble drag reduction law; the size distributions of microbubble under different conditions satisfy normal distribution, and under the same coming flow velocity, diameter of microbubble increases with increase in microporous medium porosity; with increase in ventilation, the drag reduction rate of ventilation ring model reveals 3 stages including slow increase stage, fast increase one and gradually stable one, while the drag reduction rate of ventilation section model increases linearly at a more stable increase rate until it finally stabilizes; smaller microbubbles have a higher drag reduction efficiency.