3‐D laser images of splash‐form tektites and their use in aerodynamic numerical simulations of tektite formation. (29th April 2014)

• Record Type: Journal Article
• Authors: Samson, C.; Butler, S.; Fry, C.; McCausland, P. J. A.; Herd, R. K.; Sharomi, O.; Spiteri, R. J.; Ralchenko, M.
• Is Part Of: Meteoritics & planetary science. Volume 49:Number 5(2014:May)
• Page Start: 740
• Page End: 749
• Publication Date: 2014-04-29
• Subjects: Meteorites -- Periodicals; Planetology -- Periodicals; 523.4
• DOI: 10.1111/maps.12287
• Languages: English
• ISSNs: 1086-9379

Abstract

<abstract abstract-type="main" id="maps12287-abs-0001"> <title>Abstract</title> <p>Ten splash‐form tektites from the Australasian strewn field, with masses ranging from 21.20 to 175.00 g and exhibiting a variety of shapes (teardrop, ellipsoid, dumbbell, disk), have been imaged using a high‐resolution laser digitizer. Despite challenges due to the samples' rounded shapes and pitted surfaces, the images were combined to create 3‐D tektite models, which captured surface features with a high fidelity (≈30 voxel mm⁻²) and from which volume could be measured noninvasively. The laser‐derived density for the tektites averaged 2.41 ± 0.11 g cm⁻³. Corresponding densities obtained via the Archimedean bead method averaged 2.36 ± 0.05 g cm⁻³. In addition to their curational value, the 3‐D models can be used to calculate the tektites' moments of inertia and rotation periods while in flight, as a probe of their formation environment. Typical tektite rotation periods are estimated to be on the order of 1 s. Numerical simulations of air flow around the models at Reynolds numbers ranging from 1 to 10⁶ suggest that the relative velocity of the tektites with respect to the air must have been &lt;10 m s⁻¹ during viscous deformation. This low relative velocity is consistent with tektite material being carried along by expanding gases in the early time following the impact.</p> </abstract>