Beirut explosion: Energy yield from the fireball time evolution in the first 230 milliseconds
| Autor: | Aouad, Charles, Chemissany, Wissam, Mazzali, Paolo, Temsah, Yehia, Jahami, Ali |
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| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1007/s00193-021-01031-9 |
| Popis: | The evolution of the fireball resulting from the August 2020 Beirut explosion is traced using amateur footage taken during the first $\sim$ 230 $ms$ after the detonation. 38 frames separated by $\sim$ 16.66 - 33.33 $ms$ are extracted from 6 different videos located precisely on the map. Measurements of the time evolution of the radius $R_{t}$ of the shock wave are traced by the fireball at consecutive time sequence $t$. Pixel scales for the videos are calibrated by de-projecting the existing grains silos building for which accurate drawings are available and by defining the line of sight incident angles. The energy available to drive the shock wave at early times can be calculated through $E = 10^{2b} K \rho_{o}$ where $b$ is a fitted parameter dependant on the relation between $R_t$ and $t$. $K$ is a constant depending on the ratio of specific heats of the atmosphere and $\rho_0$ is the undisturbed gas density. A total energy yield of $E \approx 1.3\times 10^{12}$ Joules with a lower bound of $9.8\times 10^{11}$ and an upper bound of $\sim 1.7\times 10^{12}$ or the equivalent of $\sim 310_{235}^{405}$ tons of T.N.T. is found. Our energy yields are different from other published studies using the same method. This can present an argument that if the compound that exploded is fuel rich ammonium nitrate (ANFO), then the actual mass that detonated is less than officially claimed. Comment: 16 pages 14 figures Time of fireball/shock wave detachment is revisited. Epoch is reduced to 170 ms. Drag model is used to track the stopping distance of the fireball. Measuring the fireball is enhanced. Hydrographic survey presented and dimensions of the crater have been used. Results compared with other published papers. Accepted to be published in Shock Waves |
| Databáze: | arXiv |
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