Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was explo...Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was exploded, two different radial strain waves were sequentially recorded by a strain gage at a distance of 80 mm from the center of charge. Through the attenuation formula of the maximum compressive strain(εrmax), the distribution of εrmax and its strain rate（ ） between the charge and gage were obtained. The effect of the two waves propagating outwards on the radial fracture of surrounding media was discussed. The results show that the two waves are pertinent to the loading of shock energy （Es） and bubble energy （Eb） against concrete surrounding charge, respectively. The former wave lasts for much shorter time than the latter. The peak values of εrmax and of the former are higher than those of the latter, respectively.展开更多
A two-bubble model with radiate(αbubble)-receive(βbubble)structure is constructed to study the energy transfer from one bubble to another.The influence of the non-dimensional distance d and the initial energy ratio...A two-bubble model with radiate(αbubble)-receive(βbubble)structure is constructed to study the energy transfer from one bubble to another.The influence of the non-dimensional distance d and the initial energy ratioψon the energy transfer rate is investigated via numerical simulation.The relative received energyε,relative jet energy J,and energy transfer ratesηare defined to quantify energy transfer.Results show that the energy transfer rate decreases with the increase of d andψwhen the two bubbles’initial radius is identical.With the increase of d,the interactions between two bubbles are weakened,and the relative received energy satisfies the law ofε∝1/d^(2).With the increase ofψ,the maximum inner pressure of theβbubble increase first and then decreases,while the jet energy of bubbleβchanges with the law of J∝ψ.It is found that the energy storage capacity increases with the bubble radius by simulating different bubble radius ratios.展开更多
We present computational results on the evolution of the shock-accelerated heavy bubbles surrounded by nitrogen with the Atwood number At = 0.497–0.677 and the emphasis is on the jet phenomenon caused by the shock fo...We present computational results on the evolution of the shock-accelerated heavy bubbles surrounded by nitrogen with the Atwood number At = 0.497–0.677 and the emphasis is on the jet phenomenon caused by the shock focusing. The multi-fluid Eulerian equation is solved by a finite volume method based on MUSCL-Hancock approach. Based on the numerical schlieren and the distributions of density and pressure, it is found that there are three typical jet structures(outward jet, no jet, inward jet) for different combinations of gas mixture inside the bubble which determine the position of shock focusing relative to the downstream pole of the heavy bubble(upstream of the pole, at the pole, downstream the pole). Compared with the inward jet, the velocity of outward jet is obviously larger. As At increases, the moment of jet formation is postponed, and the maximal values and magnifications of pressure and density increase distinctly. Therefore, the energy convergence effects are heavily enhanced with the increase of bubble gas density.展开更多
文摘Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was exploded, two different radial strain waves were sequentially recorded by a strain gage at a distance of 80 mm from the center of charge. Through the attenuation formula of the maximum compressive strain(εrmax), the distribution of εrmax and its strain rate（ ） between the charge and gage were obtained. The effect of the two waves propagating outwards on the radial fracture of surrounding media was discussed. The results show that the two waves are pertinent to the loading of shock energy （Es） and bubble energy （Eb） against concrete surrounding charge, respectively. The former wave lasts for much shorter time than the latter. The peak values of εrmax and of the former are higher than those of the latter, respectively.
基金the National Natural Science Foundation of China(Grant Nos.11872065 and 12122214)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant Nos.Y201906 and 2022019).
文摘A two-bubble model with radiate(αbubble)-receive(βbubble)structure is constructed to study the energy transfer from one bubble to another.The influence of the non-dimensional distance d and the initial energy ratioψon the energy transfer rate is investigated via numerical simulation.The relative received energyε,relative jet energy J,and energy transfer ratesηare defined to quantify energy transfer.Results show that the energy transfer rate decreases with the increase of d andψwhen the two bubbles’initial radius is identical.With the increase of d,the interactions between two bubbles are weakened,and the relative received energy satisfies the law ofε∝1/d^(2).With the increase ofψ,the maximum inner pressure of theβbubble increase first and then decreases,while the jet energy of bubbleβchanges with the law of J∝ψ.It is found that the energy storage capacity increases with the bubble radius by simulating different bubble radius ratios.
基金supported by the National Natural Science Foundation of China(Grant Nos.11172278,11302201,11472253 and 11202195)Science Foundation of China Academy of Engineering Physics(Grant No.2014B0201017)
文摘We present computational results on the evolution of the shock-accelerated heavy bubbles surrounded by nitrogen with the Atwood number At = 0.497–0.677 and the emphasis is on the jet phenomenon caused by the shock focusing. The multi-fluid Eulerian equation is solved by a finite volume method based on MUSCL-Hancock approach. Based on the numerical schlieren and the distributions of density and pressure, it is found that there are three typical jet structures(outward jet, no jet, inward jet) for different combinations of gas mixture inside the bubble which determine the position of shock focusing relative to the downstream pole of the heavy bubble(upstream of the pole, at the pole, downstream the pole). Compared with the inward jet, the velocity of outward jet is obviously larger. As At increases, the moment of jet formation is postponed, and the maximal values and magnifications of pressure and density increase distinctly. Therefore, the energy convergence effects are heavily enhanced with the increase of bubble gas density.
