0000007248 00000 n However, as soldiers are better protected from penetrating injury and surviving previously lethal exposures, limb injuries, eye and ear injuries, and traumatic brain injuries have become more prevalent. Shock Waves (2013). Shock Waves 13(2), 123–138 (2003), Dewey, J.M. The thematic issue on shock and blast waves mitigation (SBWM) focuses on the integration of physical analysis, modeling, and experiments for the study of blast waves interactions with inhomogeneous flows, and helps to provide a basis for future work in this area. E Sedov, L. I., "Propagation of strong shock waves,", Lockwood-Taylor, J., "An exact solution of the spherical blast wave problem,", Dewey JM. This is why it’s crucial to take into account pressure, impulse, distance, and all the various energies released during an explosion into account and to evaluate them. The reflected This particular type of pressure varies based on the angle of surface impacted by the shock wave. Courtesy of A. Chinnayya, University of Rouen, France. A slope of at least 2% (1% on hard surfaces) to a safe impoundment area of sufficient volume is seen as adequate. This factor requires calculation of process capacity and containment capacity. Pressure increases drastically, then drops and fluctuates—but does not disappear immediately. The present chapter deals with less-frequent and more controversial domino scenarios: domino events due to indirect escalation and external events. Rolf K. Eckhoff, in Explosion Hazards in the Process Industries (Second Edition), 2016. In fluid dynamics, a blast wave is the increased pressure and flow resulting from the deposition of a large amount of energy in a small, very localised volume. The nondimensional axis used in this figure is the same as used by Medvedev et al. The industrial version of CFD relies on the solution of Reynolds-averaged Navier–Stokes (RANS) equations. They only impact the estimated losses arising from an episode. Adds risk factors when the introduction of air into a process is a hazard possibility. Adds risk factors when temperature-related brittleness of materials is a potential concern. Mogens has key competences in advising and supporting clients and project management teams in high-risk areas. He postulated that for an idealized point source of energy, the spatial distributions of the flow variables would have the same form during a given time interval, the variables differing only in scale. (1999). HE detonate to produce a defining supersonic over-pressurization shock wave. The first of these is a shock wave - then follows a slower subsonic (slower than the speed of sound) front, followed by a negative pressure blast wind that sucks back towards the point of the explosion. Then a discussion of the concept of TNT equivalents follows. The initial shock wave is only one third of the total chemical energy release. High-order explosives (HE) are more powerful than low-order explosives (LE). Adds risk factors where minor leaks around joints, packing, glands, etc., can present an increased hazard. The ability of RANS-based CFD model to reproduce the explosion phenomenon is limited by the adoption of submodels for the mathematical representation of turbulence and combustion: most commercial CFD codes are based on simplified laminar combustion models and on the derivation of empirical correlations for the description of turbulent combustion, such as eddy-dissipation or derived models and Bray or Gülder correlations for turbulent burning velocity, which have been proved to work in the scientific literature only in the laboratory scale (see Lea and Ledin, 2002; Bjerketvedt et al., 1993 for further details). The variations with distance of the physical properties shown in Figs. Here’s another graph, which focuses on stand-off distance and overpressure—the pressure caused by a shock wave above normal atmospheric pressure. doi:10.1007/s00193-012-0414-7, Britan, A., Shapiro, H., Liverts, M., Ben-Dor, G.: Macro-mechanical modeling of blast-wave mitigation in foams. �V[%}7&*���� &��^��U'[x��n�yV?RF�A6&\�����;�x��'^��[�y���_ȷ>J ��A*$do�Ս5XU���]��t���ĉ�*j�dN�L?A��"��!��s��3_�� "aEh endstream endobj 60 0 obj 332 endobj 61 0 obj << /Type /Font /Subtype /Type1 /Name /F1 /BaseFont /Times-Roman /Encoding /WinAnsiEncoding >> endobj 62 0 obj << /Type /Font /Subtype /Type1 /Name /F3 /BaseFont /Times-Bold /Encoding /WinAnsiEncoding >> endobj 63 0 obj << /Filter /FlateDecode /Length 60 0 R >> stream From Oklahoma to Nairobi, it’s all too clear that blast-based attacks are a significant threat to both buildings and people. J. Fluid. Explain Like I'm Five is the best forum and archive on the internet for layperson-friendly explanations. Adds risk factors when air can be introduced into the process to create a mixture in a flammable range. is the density of the air and The acronym VCE stands for a group of accidents that have in common that a large cloud, accidentally formed, explodes. 0000021136 00000 n In the framework of these studies, several experimental techniques have been used with different flow configurations (polymer, dry or aqueous foams) to elucidate the phenomenon of shock attenuation. 13.1.7 for the hemispherical wave produced by the detonation of 1 kg of TNT on a rigid plane surface. However, this complexity should not prevent considering the significant role of dust explosion in the domino effect analysis. The modeling aspect of blast/shock waves mitigation was also discussed. Bethe,H.A., et al, BLAST WAVE, Los Alamos Report LA-2000, Ch. TABLE 15.2.5. The first thing to take into account is the amount and type of explosives used: Higher quantities/yield of explosive materials tend to lead to a bigger, more destructive event. Pt is a function of the hydrostatic pressure and the particle flow velocity or the dynamic pressure, the functional relationship depending on whether the flow speed is locally sub- or super-sonic, that is, whether Mu ≤ 1 or >1, where Mu ≡ u/a, u is the particle flow speed, and a the local sound speed. In spite of many studies on the subject [1–30], the mechanisms of shock propagation in such complex media still need further research. (2006) discussed various models for calculating the strength of blast waves emitted from BLEVEs. The impedances of the two materials determine how much of each occurs. Correspondence to Al-Qananwah et al. PD is the dynamic pressure, defined as 12ρu2, where ρ is the gas density and u the particle velocity. In practice, all these forms give results that are so similar they cannot be distinguished by experimental measurements. FIGURE 13.1.7. Extensive measurements of the post-shock-wave overpressure upstream and downstream of various granular filters for shock waves with steplike pressure profiles were performed by Medvedev et al. The paper presented by Del-Prete et al. The typical behavior of industrial equipment to pressure wave is sketched in Table 4.1. Corrosion and erosion. The F&EI system is not designed for public safety evaluations or environmental risk assessments, but provides some useful concepts that can be used in such assessments. 3), existing information on the foam collapse as well as heating and evaporating the liquid phase behind the blast wave is rather restricted. For example, they can diffract through a narrow opening, and refract as they pass through materials. The air gap length downstream of the filter Δ may also affect the filter performance, depending on how the filter is installed inside the duct, close to or far upstream from the protected surface (Baker et al., 1983). The loss control credit factors do not impact the F&EI score. 0000001759 00000 n Your email address will not be published. Springer, Berlin (2006), Britan, A.B., Vasilev, E.I., Kulikovskii, V.A. 15.2.39 by a single dashed line, do not indicate a dependency of ΔPexit/P on Ms. Hot rotating equipment. Shock and vibration loads transmitted through its mounting inside a structure. Mogens Dam is part of the sales, development and project management team. I. Sedov,[5] R. Latter,[6] and J. Lockwood-Taylor[7]—who had discovered it independently. H�앿o�@��\��P�;����v���H�A7B This includes a discussion of properties of fragments from various explosion types, including velocities and travel distances of ejected fragments, and penetration of fragments/missiles into human bodies. 0000003222 00000 n In: Proceeding 19th International Symposium Shock Waves, Marseille, France. For example, Petel et al. [33] presented a review paper in which they summarized the essential features of aqueous-foam barriers against blast waves impact encountered in both shock-tube experiments and full-scale field tests. Adds risk factors for loading, unloading, and warehousing of materials. The blast wave is followed by a blast wind of negative pressure, which sucks items back in towar… II. 0000033173 00000 n Journal of Neurotrauma, June 2009, Mary Ann Liebert, Inc. Cernak, I. In fluid dynamics, a blast wave is the increased pressure and flow resulting from the deposition of a large amount of energy in a small, very localised volume.