{"title":"Research on bubble jet of underwater explosion at the bottom of fixed square plate","authors":"J. Qin, Wen Yanbo, Xiangyao Meng, Ruiyuan Huang","doi":"10.1360/sspma-2020-0379","DOIUrl":null,"url":null,"abstract":"The water jet formed after the collapse of the bubble in the near-field underwater explosion can cause serious damage to the local structure of the ship, and the formation of the jet is asymmetric, which makes it difficult to measure its data in the experiment. At present, studies on the pressure time history curves of the bubble jet in the underwater explosion are still relatively rare. In order to study the characteristics of the jet, the underwater explosion test of 2.5 g TNT explosive at the bottom of fixed square plate at different detonation distances was carried out. First, the accuracy of the test data was verified by the underwater pressure sensor. Second, the image of the whole process from the explosive initiation to the bubble jet generated by the action of the bubble and the steel plate was obtained by high-speed camera. Finally, the time-history curve of water jet pressure was measured by the wall pressure sensor in the center of the steel plate, and another group of wall pressure sensors was set 15 cm away from the center of the steel plate as a control group to ensure that the measured jet data were not clutter. The test data recorded by the underwater sensor show that the error between the shock wave overpressure, the maximum bubble radius of the bubble pulse period and the empirical formula is within 10%. The results recorded by the high-speed camera and wall pressure sensor show that three jets can be observed when the burst distance is 28 cm, but the pressure time history curve is not measured due to the long burst distance. When the burst distances are 15, 17.5 and 20 cm, three jet pressure time history curves are measured. However, due to the short burst distance and the presence of a large number of bubbles between the steel plate and the water surface under the action of the shock wave, it is difficult to observe the test phenomenon with high-speed cameras. The pressure time history curve shows that three jets are generated after the first bubble pulse peak, and the jet pressure can reach 1/4 of the shock wave. The jet appears 1–3 ms after the first","PeriodicalId":44892,"journal":{"name":"Scientia Sinica-Physica Mechanica & Astronomica","volume":null,"pages":null},"PeriodicalIF":0.5000,"publicationDate":"2021-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Scientia Sinica-Physica Mechanica & Astronomica","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1360/sspma-2020-0379","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 1
Abstract
The water jet formed after the collapse of the bubble in the near-field underwater explosion can cause serious damage to the local structure of the ship, and the formation of the jet is asymmetric, which makes it difficult to measure its data in the experiment. At present, studies on the pressure time history curves of the bubble jet in the underwater explosion are still relatively rare. In order to study the characteristics of the jet, the underwater explosion test of 2.5 g TNT explosive at the bottom of fixed square plate at different detonation distances was carried out. First, the accuracy of the test data was verified by the underwater pressure sensor. Second, the image of the whole process from the explosive initiation to the bubble jet generated by the action of the bubble and the steel plate was obtained by high-speed camera. Finally, the time-history curve of water jet pressure was measured by the wall pressure sensor in the center of the steel plate, and another group of wall pressure sensors was set 15 cm away from the center of the steel plate as a control group to ensure that the measured jet data were not clutter. The test data recorded by the underwater sensor show that the error between the shock wave overpressure, the maximum bubble radius of the bubble pulse period and the empirical formula is within 10%. The results recorded by the high-speed camera and wall pressure sensor show that three jets can be observed when the burst distance is 28 cm, but the pressure time history curve is not measured due to the long burst distance. When the burst distances are 15, 17.5 and 20 cm, three jet pressure time history curves are measured. However, due to the short burst distance and the presence of a large number of bubbles between the steel plate and the water surface under the action of the shock wave, it is difficult to observe the test phenomenon with high-speed cameras. The pressure time history curve shows that three jets are generated after the first bubble pulse peak, and the jet pressure can reach 1/4 of the shock wave. The jet appears 1–3 ms after the first
近场水下爆炸气泡破裂后形成的水射流会对船舶局部结构造成严重的破坏,且射流的形成是不对称的,这使得实验中测量其数据变得困难。目前对水下爆炸气泡射流压力时程曲线的研究还比较少。为了研究射流的特性,对2.5 g TNT炸药在固定方板底部进行了不同爆轰距离的水下爆炸试验。首先,通过水下压力传感器验证了试验数据的准确性。其次,利用高速摄像机获得了从爆炸起爆到气泡与钢板相互作用产生气泡射流的整个过程的图像;最后,利用钢板中心的壁压传感器测量水射流压力时程曲线,并将另一组壁压传感器设置在距钢板中心15cm处作为对照组,以保证测量的射流数据不杂乱。水下传感器记录的试验数据表明,冲击波超压、气泡脉冲周期的最大气泡半径与经验公式的误差在10%以内。高速摄像机和壁面压力传感器记录的结果表明,当爆破距离为28 cm时,可以观测到3道射流,但由于爆破距离较长,没有测量到压力时程曲线。在爆破距离为15、17.5和20 cm时,测量了3条射流压力时程曲线。然而,由于在激波作用下钢板与水面之间爆发距离短,且存在大量气泡,使用高速摄像机很难观察到试验现象。压力时程曲线显示,在第一个气泡脉冲峰值后产生三束射流,射流压力可达到激波的1/4。喷射在第一次喷射后1-3毫秒出现