Abstract:Experimental and numerical investigations of gas flows through porous materials have been carried out. We have investigated steady and unsteady processes occurring when the gas flow interacts with porous materials. Densities ρc and porosities φg of the four open-cell-type polyurethane foams which were investigated are ρc ∼ = 26 ∼ 56 kg/m 3 and φg ∼ = 0.98 ∼ 0.95, with the foams having different structures. Experiments were conducted to determine the steady drag coefficient of the porous material at low Reynold… Show more
“…Figure 7.Comparison of the maximum total stress on the wall in the case of = 60 mm between the previous experiments (Kitagawa et al. 2001) and the present numerical study.…”
Section: Validation Studysupporting
confidence: 61%
“…1996; Kitagawa et al. 2001, 2006). When the foam was put on the shock tube end wall, it significantly deformed up to 80 % in the longitudinal direction (Skews et al.…”
Section: Validation Studymentioning
confidence: 98%
“…1996; Kitagawa et al. 2001, 2006). They chose the porous FPU foam with the characteristic length defined by the PPI.…”
Section: Validation Studymentioning
confidence: 98%
“…1996; Kitagawa et al. 2001, 2006). Five PPI values were considered herein, and the initial porosity was approximately 0.98 for 13, 30 and 50 PPI and 0.95 for 65 and 70 PPI, respectively.…”
Section: Validation Studymentioning
confidence: 98%
“…(1996) and Kitagawa et al. (2001) was long enough to neglect the expansion wave from the driver section of the shock tube; hence, the steady state of the stress–time history on the wall was achieved. The air at room temperature and atmospheric pressure was filled in the driven section.…”
This study validated a two-phase compressible flow model considering elasto-plastic porous foams. The numerical data were compared with the previous experimental results in terms of the interaction between the planar shock wave and the porous foams and the mitigation effect of a porous foam filling a straight tube on a blast wave. The porous foams in the shock tube interacted with a planar shock wave. The drag between the shocked air and the foams reduced the shock wave strength. Moreover, the flexible foam was significantly deformed by the shock wave. The validation results confirmed good agreement and consistency between the numerical and experimental data. The mitigation effect on the blast wave caused by a high explosive, where the main parameter for comparison was the location of a rigid porous foam layer inside the straight tube, was investigated. In the first case, the porous foam plate was placed on the floor, whereas in the second case, the porous foam plates were placed on the floor, sidewalls and ceiling. The total energy transferred between the porous foam and the shocked air was computed to quantitatively understand the mitigation mechanism of the porous foam on the blast wave. The heat transfer was a dominant factor for the energy transfer from the shocked air to the porous foams. The second case further mitigated the blast wave outside, and the increment of the interface area of the air/porous foam greatly affected the blast wave mitigation.
“…Figure 7.Comparison of the maximum total stress on the wall in the case of = 60 mm between the previous experiments (Kitagawa et al. 2001) and the present numerical study.…”
Section: Validation Studysupporting
confidence: 61%
“…1996; Kitagawa et al. 2001, 2006). When the foam was put on the shock tube end wall, it significantly deformed up to 80 % in the longitudinal direction (Skews et al.…”
Section: Validation Studymentioning
confidence: 98%
“…1996; Kitagawa et al. 2001, 2006). They chose the porous FPU foam with the characteristic length defined by the PPI.…”
Section: Validation Studymentioning
confidence: 98%
“…1996; Kitagawa et al. 2001, 2006). Five PPI values were considered herein, and the initial porosity was approximately 0.98 for 13, 30 and 50 PPI and 0.95 for 65 and 70 PPI, respectively.…”
Section: Validation Studymentioning
confidence: 98%
“…(1996) and Kitagawa et al. (2001) was long enough to neglect the expansion wave from the driver section of the shock tube; hence, the steady state of the stress–time history on the wall was achieved. The air at room temperature and atmospheric pressure was filled in the driven section.…”
This study validated a two-phase compressible flow model considering elasto-plastic porous foams. The numerical data were compared with the previous experimental results in terms of the interaction between the planar shock wave and the porous foams and the mitigation effect of a porous foam filling a straight tube on a blast wave. The porous foams in the shock tube interacted with a planar shock wave. The drag between the shocked air and the foams reduced the shock wave strength. Moreover, the flexible foam was significantly deformed by the shock wave. The validation results confirmed good agreement and consistency between the numerical and experimental data. The mitigation effect on the blast wave caused by a high explosive, where the main parameter for comparison was the location of a rigid porous foam layer inside the straight tube, was investigated. In the first case, the porous foam plate was placed on the floor, whereas in the second case, the porous foam plates were placed on the floor, sidewalls and ceiling. The total energy transferred between the porous foam and the shocked air was computed to quantitatively understand the mitigation mechanism of the porous foam on the blast wave. The heat transfer was a dominant factor for the energy transfer from the shocked air to the porous foams. The second case further mitigated the blast wave outside, and the increment of the interface area of the air/porous foam greatly affected the blast wave mitigation.
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