Three-dimensional turbulent velocity field and air entrainment of the 22 March 1944 Vesuvius eruption plume
Three-dimensional turbulent velocity field and air entrainment of the 22 March 1944 Vesuvius eruption plume
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1944 年 3 月 22 日维苏威火山喷发羽流的三维湍流速度场和空气夹带
DOI：
10.1007/s00445-024-01703-1
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发表时间：
2024
影响因子：
3.5
通讯作者：
Coonin, Allie N.
中科院分区：
文献类型：
--
作者：
Andrews, Benjamin J.;Coonin, Allie N.
湍流空气夹带到爆炸性火山喷流决定是否喷发将产生浮力羽流，火山碎屑密度流，或两者兼而有之。大多数以前的研究卷吸包括数值模型和模拟实验室实验，与相对较少的观察自然喷发。现有的卷吸观测一般是时间和空间平均的测量，不提供有关卷吸机制的信息。我们调查的空间和时间的变化夹带的3月22日普林尼阶段的1944年喷发的山。维苏威火山使用特征跟踪测速（FTV）算法，应用于美国海军收集的电影，并由美国国家档案馆数字化。我们描述了一种新的技术来估计归一化亮度的三维羽状形态。将来自FTV算法的2D速度场投影到那些3D表面上提供3D速度场。速度场的发散量化了局部膨胀和卷吸，并表明尽管羽流中存在千米尺度的涡流，卷吸和膨胀发生在数百米量级的长度尺度上。在夹带区域上对向内定向的速度进行积分量化了局部空气夹带率。我们发现，5.4-6.1 × 107 m3 s-1的空气卷吸发生在约三分之一的观测到的羽流边缘，产生的平均卷吸速度约为2.8 ms-1。将这些速率外推至整个烟羽表明，总卷吸量为1-3 × 108 m3 s-1。卷吸速度的大小约为沿羽流边缘的湍流强度大小的沿着6%，表明后者可能接近中心线羽流速度，并建议对这种和类似的喷发使用0.06的卷吸系数，即，具有相对高动量主导区域的强羽流。
Turbulent air entrainment into explosive volcanic jets determines whether an eruption will produce buoyant plumes, pyroclastic density currents, or both. Most previous studies of entrainment consist of numerical models and analog laboratory experiments, with relatively few observations of natural eruptions. The existing observations of entrainment are generally time- and space-averaged measurements, which do not provide information regarding the mechanisms of entrainment. We investigate spatial and temporal variations in entrainment of the March 22 Plinian phase of the 1944 eruption of Mt. Vesuvius using a feature tracking velocimetry (FTV) algorithm applied to film collected by the U.S. Navy and digitized by the U.S. National Archives. We describe a novel technique to estimate the 3D plume morphology from normalized brightness. Projection of the 2D velocity fields from the FTV algorithm onto those 3D surfaces provides 3D velocity fields. The divergence of the velocity fields quantifies local expansion and entrainment and shows that although kilometer scale eddies are present in the plume, entrainment and expansion occur over length scales on the order of hundreds of meters. Integrating the inward directed velocities over the entraining regions quantifies local air entrainment rates. We find that entrainment of 5.4–6.1 × 107m3s-1air occurs over about one-third of the observed plume margins, yielding an average entrainment velocity of ~ 2.8 ms-1. Extrapolation of those rates to the entire plume indicates total entrainment of 1–3 × 108m3s-1. The entrainment velocity has a magnitude ~ 6% of the magnitude of the turbulence intensity along the plume margins, indicating that the latter may approximate the centerline plume velocity and suggesting use of entrainment coefficient of 0.06 for this and similar eruptions, i.e., strong plumes with a relatively high momentum-dominated region.
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DOI：
10.1016/j.jvolgeores.2004.11.001
发表时间：
2005-03-15
影响因子：
2.9
作者：
Burgisser, A;Bergantz, GW;Breidenthal, RE
通讯作者：
Breidenthal, RE
影响因子：
5.3
作者：
Jessop, D. E.;Gilchrist, J.;Roche, O.
通讯作者：
Roche, O.
DOI：
10.1016/j.jvolgeores.2017.07.006
发表时间：
2017-09-01
影响因子：
2.9
作者：
Aubry, Thomas J.;Jellinek, A. Mark;Dunning, Jack
通讯作者：
Dunning, Jack
从工业光度立体的梯度直接正则化表面重建
DOI：
--
发表时间：
2013
期刊：
Computers in industry (Print)
影响因子：
--
作者：
M. Harker;P. O’Leary
通讯作者：
P. O’Leary
影响因子：
3.5
作者：
Andrews, Benjamin J.
通讯作者：
Andrews, Benjamin J.