Abstract During the operation of a seismic airgun source, a certain amount of compressed high-pressure air is released from the airgun chamber into the surrounding water, generating an expanding toroidal bubble attached to the airgun-body. The subsequent oscillations of the bubble generate low-frequency pressure waves, which are used to map the ocean subbottom, e.g., to locate oil and gas reserves. The bubble dynamic behavior and the emitted pressure waves are inevitably influenced by the airgun-body. However, the bubble-airgun-body interaction is far from well understood. This paper investigates the strong interaction between a long cylinder and an attached toroidal bubble via hundreds of boundary integral simulations, aiming to provide new physical insights for airgun-bubble dynamics. Firstly, the overall physical phenomena are discussed and three types of bubble collapse patterns are identified, namely (i) upward jetting due to gravity, (ii) annular jet toward the cylinder body and (iii) weak/no jet. Thereafter, we investigate the effects of the cylinder radius, initial bubble pressure and Froude number on the bubble oscillation period and the pressure wave induced by the bubble. At last, the impact of a cylinder on a Sercel type airgun-bubble is discussed with a particular focus on the spectrum of the pressure waves.

中文翻译：

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圆柱表面环形气泡动力学及其在地球物理勘探中的应用

摘要 地震气枪震源在工作过程中，一定量的压缩高压空气从气枪室中释放到周围的水中，在气枪体上产生一个不断膨胀的环形气泡。随后气泡的振荡产生低频压力波，用于绘制海洋底层，例如，定位石油和天然气储量。气泡动力学行为和发射的压力波不可避免地受到气枪体的影响。然而，气泡-气枪-身体的相互作用还远未得到很好的理解。本文通过数百个边界积分模拟研究了长圆柱体和附着的环形气泡之间的强相互作用，旨在为气枪气泡动力学提供新的物理见解。首先，讨论了整体物理现象并确定了三种类型的气泡破裂模式，即（i）由于重力向上喷射，（ii）朝向圆柱体的环形喷射和（iii）弱/无喷射。此后，我们研究了圆柱半径、初始气泡压力和弗劳德数对气泡振荡周期和气泡引起的压力波的影响。最后，讨论了气缸对 Sercel 型气枪气泡的影响，特别关注压力波的频谱。初始气泡压力和弗劳德数对气泡振荡周期和气泡引起的压力波的影响。最后，讨论了气缸对 Sercel 型气枪气泡的影响，特别关注压力波的频谱。初始气泡压力和弗劳德数对气泡振荡周期和气泡引起的压力波的影响。最后，讨论了气缸对 Sercel 型气枪气泡的影响，特别关注压力波的频谱。