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吴蓓蓓, 刘桦. 海底火山喷发大气冲击波激发的轴对称海啸波数值模型[J]. 力学学报.
引用本文: 吴蓓蓓, 刘桦. 海底火山喷发大气冲击波激发的轴对称海啸波数值模型[J]. 力学学报.
Numerical Model of Axisymmetric Tsunami Waves Generated By Atmospheric Pressure Shock Waves of Submarine Volcanic Eruption[J]. Chinese Journal of Theoretical and Applied Mechanics.
Citation: Numerical Model of Axisymmetric Tsunami Waves Generated By Atmospheric Pressure Shock Waves of Submarine Volcanic Eruption[J]. Chinese Journal of Theoretical and Applied Mechanics.

海底火山喷发大气冲击波激发的轴对称海啸波数值模型

Numerical Model of Axisymmetric Tsunami Waves Generated By Atmospheric Pressure Shock Waves of Submarine Volcanic Eruption

  • 摘要: 海底火山喷发引发海啸具有多源激发机制,包括水下爆炸、边坡失稳、火山口坍塌、碎屑流、地震以及大气扰动。为了深入认识移动气压扰动激发海啸的机理,探究气压扰动参数对水波形态的影响规律,本文在Chwang & Wu (1977) 提出的柱面孤立波Boussinesq模型的基础上,考虑水面移动大气扰动压强作用,建立了由火山喷发激发的轴对称移动气压场所驱动的海啸波数值模型。采用不同地形上柱面波传播算例验证了模型的精确性与稳定性。数值模拟了2022年汤加火山喷发大气扰动激发海啸事件,并与太平洋DART浮标实测数据比较,较好地复演了大气扰动驱动的波动。讨论了轴对称气压扰动的径向移速、强度及尺度对海啸波的影响,发现气压移速与浅水波速的相对大小显著影响波幅放大因子,当二者接近时将激发Proudman共振,但气压强度和尺度对波幅放大因子的影响相对较小。

     

    Abstract: Tsunami waves induced by submarine volcanic eruption have multi-physical mechanisms, such as underwater explosions, pyroclastic flows, flank and lava bench failures, column and caldera collapses, and atmospheric pressure disturbances. Based on the cylindrical Boussinesq model proposed by Chwang & Wu (1977), a numerical model for tsunami waves driven by axisymmetric moving atmospheric disturbances is developed to understand how moving pressure fields lead to tsunamis and explore how pressure parameters affect water wave patterns. The model is verified against numerical results of cylindrical wave propagation on different terrains. The computed wave elevations induced by the atmospheric disturbance of the 2022 Tonga volcanic tsunami event agree well with the DART buoy data in the Pacific Ocean. The effects of the radial velocity, spatial scale, and strength of pressure disturbances are discussed. It turns out that the water wave pattern is highly related to the pressure radial velocity, and the Proudman resonance is triggered when the pressure velocity approaches the shallow water wave speed. However, there is less influence of the spatial scale and strength of the pressure disturbance on the amplitude amplification factor.

     

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