The mysterious grooves of Volcán Bárcena: a review of the role of streamwise counter-rotating vortices during erosion by dilute pyroclastic density currents
The mysterious grooves of Volcán Bárcena: a review of the role of streamwise counter-rotating vortices during erosion by dilute pyroclastic density currents
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巴尔塞纳火山的神秘凹槽：稀火山碎屑密度流侵蚀过程中流向反向旋转涡流作用的回顾
DOI：
10.1007/s00445-021-01440-9
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发表时间：
2021
影响因子：
3.5
通讯作者：
J. Austin
中科院分区：
文献类型：
--
作者：
S. Kieffer;E. Meiburg;J. Best;J. Austin
虽然在高能量通道的火山碎屑密度流（PDC）的侵蚀造成了巨大的损害，这种侵蚀的影响的分析是稀疏的科学文献相比，沉积过程的观察和解释。在本文中，我们回顾了观察表面的PDCs侵蚀的凹槽，提供信息的侵蚀过程。我们假设，在某些情况下，刻槽的PDC的边界层中的流向涡和审查可能的流体动力学不稳定性，可以引起这样的涡。对于墨西哥巴尔塞纳火山的突出凹槽，我们提出了一种流体动力学不稳定性，我们称之为“凹槽不稳定性”，发生并导致形成侵蚀性反向旋转涡。当颗粒浓度边界层厚度δ c大于速度（剪切）边界层厚度δ u时，即，L=δ c /δ u >1。在水下浊流中，这些涡旋具有~25*δ c的典型波长。如果将这一关系应用于巴尔塞纳火山上形成的凹槽，推断的颗粒浓度边界层估计厚度小于1米。我们假设，当水力超临界流的上侧翼改变为亚临界流约半山腰下山时，发生了一个过渡的侵蚀槽和沉积沙丘在巴尔塞纳火山。我们呼吁注意边界层动力学在侵蚀性火山碎屑密度流的尺寸，难以在实验室实验中定量缩放，通常不解决计算，并需要将这种动态模型的PDC动态。
Although erosion during high-energy passage of a pyroclastic density current (PDC) causes great damage, analyses of the effects of such erosion are sparse in scientific literature compared to observations and interpretations of depositional processes. In this paper, we review observations of surfaces where PDCs have eroded sets of grooves that provide information on the erosion process. We postulate that in some cases, the grooves were carved by streamwise vortices in the boundary layer of the PDC and review possible fluid dynamic instabilities that can give rise to such vortices. For the prominent grooves at Volcán Bárcena, Mexico, we propose that a fluid dynamic instability, which we dub the “groovy instability,” occurred and caused formation of erosive counter-rotating vortices. This instability occurs when the particle concentration boundary layer thickness, δ c , is larger than the velocity (shear) boundary layer thickness, δ u , i.e., L=δ c /δ u >1. In subaqueous turbidity currents, these vortices have a typical wavelength of ~25*δ c . If this relation is applied to the grooves formed on Volcán Bárcena, the inferred particle concentration boundary layer is estimated to have been <1 m thick. We postulate that a transition between erosion of grooves and deposition of dunes at Volcán Bárcena occurred when hydraulically supercritical flow on the upper flanks changed to subcritical flow about halfway down the mountain. We call attention to boundary layer dynamics in erosive pyroclastic density currents at a dimension that is difficult to scale quantitatively in laboratory experiments and is usually not resolved computationally and to the need for incorporating such dynamics into models of PDC dynamics.
影响因子：
3.5
作者：
Douillet, Guilhem Amin;Tsang-Hin-Sun, Eve;Kueppers, Ulrich;Letort, Jean;Pacheco, Daniel Alejandro;Goldstein, Fabian;Von Aulock, Felix;Lavallee, Yan;Hanson, Jonathan Bruce;Bustillos, Jorge;Robin, Claude;Ramon, Patricio;Hall, Minard;Dingwell, Donald B.
通讯作者：
Dingwell, Donald B.
影响因子：
3.5
作者：
Douillet, Guilhem Amin;Pacheco, Daniel Alejandro;Kueppers, Ulrich;Letort, Jean;Tsang-Hin-Sun, Eve;Bustillos, Jorge;Hall, Minard;Ramon, Patricio;Dingwell, Donald B.
通讯作者：
Dingwell, Donald B.
影响因子：
42.1
作者：
Lube, Gert;Breard, Eric C.;Esposti-Ongaro, Tomaso;Dufek, Josef;Brand, Brittany
通讯作者：
Brand, Brittany