Investigating projectile penetration into immersed granular beds via CFD-DEM coupling
Investigating projectile penetration into immersed granular beds via CFD-DEM coupling
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DOI：
10.1007/s10035-023-01364-5
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发表时间：
2023-09
期刊：
影响因子：
2.4
通讯作者：
Jiayu Lin;Tao Zhao;Mingjing Jiang
中科院分区：
文献类型：
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作者：
Jiayu Lin;Tao Zhao;Mingjing Jiang
弹丸侵彻浸没颗粒层是地球物理学和工程学中的一种常见现象，包括各种情况，如浸没火山口形成和近海土壤-结构相互作用。它涉及流体和颗粒物质之间复杂的物理相互作用。在这项研究中，我们使用耦合的计算流体动力学和离散元方法（CFD-DEM）研究了弹丸穿透浸入流体中的颗粒床的动力学。颗粒床由多分散颗粒组成，抛射体被模拟为刚性球体。弹坑形成的形态，弹丸的动力学，并在浸没的情况下的阻力特性进行了详细的研究，并比较干燥的情况。数值结果表明，弹丸的最终侵彻深度符合由实验观测得到的经验关系式，侵彻过程中的落高和阻力分别服从幂律函数和修正的广义Poncelet定律。间隙流体不仅提供直接拖曳力，而且通过提高颗粒床的广义摩擦力和有效粘度来增强颗粒床的有效拖曳力。对不同阶段的速度演化和接触力网络进行了微观分析，以阐明侵彻动力学。该研究为深入了解弹丸侵彻机制和间隙流体对颗粒介质的影响提供了见解，这在工程应用中至关重要，例如海上锚固，软沉积物中的球侵彻试验以及土壤-结构相互作用。图形摘要
Projectile penetration into an immersed granular bed is a common phenomenon in both geophysics and engineering, encompassing various scenarios such as immersed crater formation and offshore soil-structure interaction. It involves the complex physical interaction between the fluid and granular materials. In this study, we investigate the dynamics of projectile penetration into a granular bed immersed in a fluid using a coupled computational fluid dynamics and discrete element method (CFD-DEM). The granular bed is composed of polydisperse particles, and the projectile is modeled as a rigid sphere. The morphology of crater formation, the dynamics of the projectile, and the drag force characteristics in immersed cases were studied in detail and compared to the dry scenario. The numerical results show that the final penetration depth of the projectile follows an empirical relation derived from experimental observations, where the falling height and the drag force during penetration obey a power-law function and a modified generalized Poncelet law, respectively. The interstitial fluid not only provides direct drag force, but also enhances the effective drag force of the granular bed by improving its generalized friction and effective viscosity in different configurations. Micro-analyses of the velocity evolution and contact force network in different stages of the fluid–solid interaction were performed to clarify the penetration dynamics. This research provides insights into the mechanisms of projectile penetration and the effects of interstitial fluid on granular media, which are crucial in engineering applications such as offshore anchoring, ball penetration tests in soft sediments, and soil-structure interactions.Graphical Abstract