Investigating the conditions behind the formation of pyroclast textures and lava flow morphologies is important to understand the dynamics of submarine volcanic eruptions, which are hard to observe. The development of clast textures and lava morphologies depends on the competing effects of their eruption rates and the rates of solidification. While eruption rates are governed by subsurface magmatic processes, the solidification timescales depend on the rate of heat loss from lava to the external water. However, the effect of the speed of lava flow or clast on their solidification timescales under two-phase (liquid water and vapor bubbles) water boiling conditions is poorly constrained. Using laboratory experiments with remelted igneous rocks, we investigate the effect of the relative motion between lava and external water on its cooling timescale. We use a range of water speed (0–12.5 cm s⁻¹) in our experiments while keeping our sample stationary to simulate a range of relative speed between lava and ambient water. Using transient heat transfer modeling, we find that heat flux from the surface of the sample to the external water overall increases with increasing water speed. We find heat transfer coefficients of up to ∼1.72 × 10³ W m⁻² K⁻¹. The implications of high heat flux on the formation of solid lava crust under submarine conditions are discussed.

中文翻译：

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蒸汽泡和对海底喷发期间熔岩和火山碎屑冷却速率的速度控制

研究火山碎屑纹理和熔岩流形态形成背后的条件对于了解难以观察到的海底火山喷发的动力学非常重要。碎屑纹理和熔岩形态的发展取决于它们的喷发率和凝固率的竞争效应。虽然喷发率受地下岩浆过程控制，但凝固时间尺度取决于从熔岩到外部水的热量损失率。然而，在两相（液态水和气泡）水沸腾条件下，熔岩流或碎屑的速度对其凝固时间尺度的影响很少受到限制。通过使用重熔火成岩的实验室实验，我们研究了熔岩和外部水之间的相对运动对其冷却时间尺度的影响。^-1 ) 在我们的实验中，同时保持我们的样品静止以模拟熔岩和环境水之间的相对速度范围。使用瞬态传热模型，我们发现从样品表面到外部水的热通量总体上随着水速的增加而增加。我们发现传热系数高达 ∼1.72 × 10 ³  W m ^-2  K ^-1。讨论了高热通量对海底条件下固体熔岩壳形成的影响。