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Central uplift collapse in acoustically fluidized granular targets: Insights from analog modeling
Meteoritics and Planetary Science ( IF 2.2 ) Pub Date : 2020-02-05 , DOI: 10.1111/maps.13442
M. A. Dörfler 1 , T. Kenkmann 1
Affiliation  

Depending on their sizes, impact craters have either simple or complex geometries. Peak‐ring craters such as the Chicxulub impact structure possess a single interior ring of peaks and hills and a flat interior floor. The exact mechanisms leading to the formation of a morphological peak‐ring are still a matter of debate. In this study, analog modeling was used to study the flow field of a collapsing central uplift. A 3‐D‐printed cast was used to bring the analog material in the shape of an overheightened central uplift that was based on numerical modeling. The cast was then quickly removed and the central peak collapsed, forming a flattened broad mound that spread out onto the annular moat of the crater cavity. A subwoofer was used to fluidize the granular target material. The kinematics of the collapse were analyzed with the aid of particle image velocimetry, revealing a downward and outward collapse of the central uplift. This mode of collapse is partly in agreement with numerical models, in particular for the initial and middle phases. The overthrusting of the collapsing central peak onto the inward moving crater floor predicted by numerical modeling was observed, though to a lesser degree. A peak‐ring, however, could not be reproduced since the collapse came to a halt before the central peak was completely leveled. Nevertheless, the method provides qualitative insights into the kinematics of collapse phenomena. This experimental study provides independent support of the theory of acoustic fluidization, in addition to numerical simulations.

中文翻译:

声学流化颗粒目标的中央隆起塌陷:模拟建模的见解

根据撞击坑的大小,撞击坑具有简单或复杂的几何形状。峰环坑(如Chicxulub冲击结构)具有一个峰顶和丘陵内部环以及一个平坦的内部地板。导致形成形态峰环的确切机制仍存在争议。在这项研究中,模拟模型被用来研究坍塌的中央隆升的流场。使用3D打印的铸件将模拟材料制成基于数值模型的过度升高的中央隆起形状。然后迅速除去铸件,中央峰塌陷,形成一个扁平的宽丘,并扩展到火山口腔的环形annular沟上。超低音扬声器用于流化颗粒状靶材。借助粒子图像测速仪分析了塌陷的运动学,揭示了中央隆升的向下和向外塌陷。这种崩溃模式与数值模型部分吻合,特别是对于初始阶段和中间阶段。尽管数值较小,但观察到坍塌的中心峰在向内移动的火山口底板上的超推作用。但是,由于在中心峰完全变平之前崩溃就停止了,因此无法复制峰环。然而,该方法提供了对坍塌现象运动学的定性见解。除数值模拟外,该实验研究还为声流化理论提供了独立的支持。揭示了中央隆升的向下和向外崩溃。这种崩溃模式与数值模型部分吻合,特别是对于初始阶段和中间阶段。尽管数值较小,但观察到坍塌的中心峰在向内移动的火山口底板上的超推作用。但是,由于在中心峰完全变平之前崩溃就停止了,因此无法复制峰环。然而,该方法提供了对坍塌现象运动学的定性见解。除数值模拟外,该实验研究还为声流化理论提供了独立的支持。揭示了中央隆升的向下和向外崩溃。这种崩溃模式与数值模型部分吻合,特别是对于初始阶段和中间阶段。尽管数值较小,但观察到坍塌的中心峰在向内移动的火山口底板上的超推作用。但是,由于在中心峰完全变平之前崩溃就停止了,因此无法复制峰环。然而,该方法提供了对坍塌现象运动学的定性见解。除数值模拟外,该实验研究还为声流化理论提供了独立的支持。尽管数值较小,但观察到坍塌的中心峰在向内移动的火山口底板上的超推作用。但是,由于在中心峰完全变平之前崩溃就停止了,因此无法复制峰环。然而,该方法提供了对坍塌现象运动学的定性见解。除数值模拟外,该实验研究还为声流化理论提供了独立的支持。尽管数值较小,但观察到坍塌的中心峰在向内移动的火山口底板上的超推作用。但是,由于在中心峰完全变平之前崩溃就停止了,因此无法复制峰环。然而,该方法提供了崩溃现象运动学的定性见解。除数值模拟外,该实验研究还为声流化理论提供了独立的支持。
更新日期:2020-03-31
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