垂直振动水柱中气泡下沉机理  

Mechanism of bubble sinking in vertically vibrating water

作　　者：赵小刚 杨浩然 张琪 程琳[1] 张翔宇[1] 王凤龙 段丞博 卓伟 徐春龙[1] 侯兆阳[1] Zhao Xiao-Gang;Yang Hao-Ran;Zhang Qi;Cheng Lin;Zhang Xiang-Yu;Wang Feng-Long;Duan Cheng-Bo;Zhuo Wei;Xu Chun-Long;Hou Zhao-Yang(College of Science,Chang’an University,Xi’an 710064,China;School of Materials Science and Engineering,Chang’an University,Xi’an 710064,China)

机构地区：[1]长安大学理学院,西安710064 [2]长安大学材料科学与工程学院,西安710064

出　　处：《物理学报》2020年第24期185-193,共9页Acta Physica Sinica

基　　金：中央高校基本科研业务费专项资金(批准号:300102128301,300102128302);陕西省自然科学基础研究计划(批准号:2019JQ-507);国家大学生创新创业训练计划(批准号:201910710174)资助的课题.

摘　　要：对装有水的容器施加垂直振动,水中的气泡可能出现下沉的现象.针对球形气泡构建了基于理想气体方程的气泡运动学模型,该模型考虑了Basset力对气泡运动的影响.观察到气泡的运动呈振荡形式,存在一个临界深度,气泡在临界深度时稳定振荡,在临界深度以上时上升,在临界深度以下时下沉.采用分离气泡运动和引入收敛因子的方法对Basset力进行理论求解,并通过等步长复合梯形公式对Basset力进行数值求解.模型的数值模拟结果表明:附加质量力是气泡下沉的关键因素,而Basset力对气泡下沉的临界深度和气泡下沉的前期轨迹无明显影响,但对气泡下沉的后期轨迹有较大影响.采用去噪、二值化、填充图像等数字图像处理的办法提取气泡的特征尺寸,可提高实验参数测量的准确性,使气泡下沉的临界深度与理论值相匹配.When a container filled with water is subjected to vertical vibration,bubbles in the water may sink.This phenomenon exists widely in the field of engineering,and has a non-negligible influence on aerospace engineering and ship engineering.Therefore,it is of great significance to study the movement of bubble sinking in order to reduce the adverse effect caused by bubble sinking in the project.In previous papers,the effect of Basset force on bubble motion was usually ignored.In this paper,the bubble motion model based on the ideal gas equation is built for spherical bubbles,and the influence of the Basset force on the bubble motion is considered in the model.In the process of solving Basset force,the motion is directly separated and the convergence factor is introduced in theoretical solution.The equal step composite trapezoid formula is applied to the numerical solution.The results of numerical calculation show that the added mass force is important for bubble sinking.We find that the Basset force has no effect on the stable oscillation position of bubble,but it can accelerate the later trajectory of bubble motion.Importantly,we demonstrate that the bubble is hindered by the following component forces:buoyancy,viscous resistance,and flow thrust(which are ordered from large to small value).The movement of the bubble is observed to be in the form of oscillation,and there exists a depth,i.e.a critical depth:the bubble oscillate steadily at this depth,specifically,the bubble rises above this depth and sinks below this depth.When the vibration pressure changes,the location of the bubble’s stable oscillation will also be affected.The origin can be ascribed to the change of added mass force caused by the change of vibration pressure.Meanwhile,on the basis of digital image processing method,denoising,filtering,local stretching,image binarization and image filling are used to extract the characteristic dimension of bubbles.The theoretical value of the critical depth of bubble sinking matches the experimental result and t

关 键 词：垂直振动 气泡下沉 稳定振荡 Basset力 

分 类 号：O552.4[理学—热学与物质分子运动论]