Peak Overpressure Research Articles

Dust raising law of gas explosion in a 3D reconstruction real tunnel: Based on ALE-DEM model

A method based on the combination of finite element and discrete element theories is proposed to reveal the dust raising law of gas explosion shockwaves in 3D reconstructed real tunnels. The influence of a real tunnel's wall structure on shock wave overpressure is simulated and explored, the mechanism of action of the gas explosion shock wave on coal dust particles is revealed. Results indicate Peak overpressure of the fluid near the uneven walls exceeds that at the center of the tunnel by up to 165%. The sharp increase in shock wave overpressure causes a rapid rise in coal dust. Simultaneously, coal dust can decrease the overpressure at the shock wave front by 6.3% to 34.6%. During the shock wave attenuation period, the ratio between the maximum rise height of coal dust and the total displacement decreases as the distance between coal dust and the explosion source increases.

Experimental study on the effects of ignition position and inhomogeneous concentration on vented hydrogen deflagrations in a 7 m3 chamber

Vented inhomogeneous hydrogen deflagrations are conducted in a 7 m3 chamber. The effects of ignition position and inhomogeneous concentration are studied. The results show that a coupling flame structure of jet fire and flame bubble is first observed. In the case of top ignition, a M-shaped flame structure forms for average hydrogen concentration C¯H2≤ 10.14 vol%. In the cases of center ignition and bottom ignition, the flame bubble rapidly expands towards the walls and the horizontal propagation speed of upper part of flame bubble is obviously higher than that of lower part of flame bubble for C¯H2≥ 11.27 vol%. Moreover, the speed of horizontal flame front quickly decreases as the flame front moves away from the centerline of hydrogen jet. Three overpressure peaks appear in all scenarios, namely Popen, Phel and Pvib, which results from the vent failure, Helmholtz-type oscillations and thermo-acoustic oscillations respectively. The maximum overpressure dominated by Popen is nearly insensitive to C¯H2for top ignition. However, the maximum overpressure induced by center ignition or bottom ignition significantly increases when C¯H2≥ 10.14 vol%. For a given C¯H2, Pvib induced by bottom ignition is always the largest.

Experimental Study on the Influence of Water Barrier Placement Position on Shock Wave Pressure Peak

According to the self-built experimental platform, the shock wave experiment with and without a water barrier was carried out, the influence of the existence of a water barrier on the shock wave pressure peak was compared, and the influence of the water placement position on the attenuation effect of the pressure peak was studied. The experimental results show that the existence of a water barrier can completely attenuate the shock wave over-pressure peak, but the formation of aerosol clouds driven by high-speed airflow after the water barrier wave will produce corresponding dynamic pressure peaks. The effect of attenuating the pressure peak will not be achieved near the water barrier, and the pressure peak can be effectively attenuated farther away from the water barrier.

Experimental and numerical investigation of badarpur sand subjected to air-blast loading

In the present study, the results of experimental and numerical investigation of Badarpur sand subjected to air-blast loading generated from a laboratory-scale blast simulator are presented. The air-blast loading on the sand specimen is simulated experimentally using a vertical shock tube test facility to investigate the stress wave attenuation and vibrational characteristics of the Badarpur sand. The peak stress wave pressure and peak particle acceleration are recorded using the synchronized pressure transducers and triaxial accelerometers embedded inside the sand specimen. A stress enhancement of about 1.25-2.69 times the peak over-pressure is observed at the top one-third layer of the sand due to its compaction by the stress wave generated upon the blast wave impact. The stress wave intensity first increases and then rapidly decreases with the depth of the sand specimen. The amplitude of the peak particle acceleration is also observed to attenuate with the depth of the sand specimen. Further, based on the experimental results, the empirical equations are developed to predict peak particle velocity against the scaled distance with a power law index of 3.9, 2.5, and 3.0 for dense-coarse, dense-fine, and medium-dense fine sand, respectively. The numerical model of the vertical shock tube and sand specimens are also developed based on the Arbitrary Lagrangian-Eulerian formulation, commercially available in finite element simulation package LS DYNA and the results are validated with the experimental data.

Multiple impact effects of helium-driven shocks on thin fiber-metal laminates

Fiber Metal Laminates (FMLs) have garnered considerable attention and are increasingly being utilized in the development of protective armors for explosion and ballistic scenarios. While most research has focused on assessing the response of FMLs to single impacts, real battlefield situations often require shielding structures to endure multiple impacts. Thus, this study revolves around the creation of hybrid FMLs designed for shock shielding purposes. The primary focus is on how these laminates withstand repetitive impacts from high-intensity shock waves, aiming to pinpoint the optimal sequence that offers the highest resistance against multiple shock impacts. To establish effective shielding, a multi-layered FML configuration is employed. This configuration incorporates AA6061-T6 facing plates, ballistic-grade synthetic materials like aramid/epoxy ply, and ultra-high molecular weight polyethylene (UHMWPE)/epoxy ply. Additionally, a paperboard/epoxy lamina is introduced to induce functional grading based on layerwise shock impedance mismatches. Shock impact experiments are conducted using a shock tube equipped with helium as the driver gas. Critical shock parameters, including Mach Number, positive impulse, and peak overpressure, are meticulously evaluated. For validation purposes, a numerical model is employed to project the damage profile as a function of radial distance across different laminate sequences. The study unveils that ply deformations are strongly influenced by the arrangement of core layers, particularly the positions of the paperboard and UHMWPE layers within the core structure. To contextualize the findings, the shock impact results obtained from this study are compared with those from prior experiments that employed nitrogen-driven shocks.

Experimental study on the overpressure variation and flame mode of premixed fuel-air deflagration in a semi-closed enclosure

A small scale combustible gas venting explosion experimental system with a volume of 0.002 m3/0.0035 m3 was established, and the venting explosion experiments of ‘petroleum fuel vapor-air mixture’ under various vent sizes were conducted. The characteristics of overpressure and flame parameters under different vent sizes were obtained and the different venting modes were classified. The research results show that the overpressure history of petroleum fuel vapor/air mixture during the venting explosion process could be divided into four types, and four typical overpressure peaks induced by various phenomena were captured. With increasing venting coefficient Kv, the number of overpressure peaks decreases, but the value of overpressures gradually increases. When the value of Kv was relatively small (Kv ≤ 3.329) a ball or mushroom flame cloud was formed in the external field. When the value of Kv was comparatively large (4.560 ≤ Kv), a jet-like flame was formed in the external field. With the increase of the venting coefficient Kv, the internal maximum overpressure peak, the external maximum overpressure peak along vertical direction, the external flame height dimensionless number along the vertical direction and the external flame speed dimensionless number along the vertical direction showed an increasing trend, while the external flame diameter dimensionless number along the horizontal direction and the external flame speed dimensionless number along horizontal direction showed an decreasing trend. If treat ‘the least number of overpressure peaks’ and ‘the external explosion doesn’t occur’ as the ideal state of the venting explosion process, the vent opening needs to be set to ensure that 4.560 ≤ Kv ≤ 8.585.

Mitochondrial Dysfunction after Repeated Mild Blast Traumatic Brain Injury Is Attenuated by a Mild Mitochondrial Uncoupling Prodrug.

Mild traumatic brain injury (mTBI) results in impairment of brain metabolism, which is propagated by mitochondrial dysfunction in the brain. Mitochondrial dysfunction has been identified as a pathobiological therapeutic target to quell cellular dyshomeostasis. Further, therapeutic approaches targeting mitochondrial impairments, such as mild mitochondrial uncoupling, have been shown to alleviate behavioral alterations after TBI. To examine how mild mitochondrial uncoupling modulates acute mitochondrial outcomes in a military-relevant model of mTBI, we utilized repeated blast overpressure of 11 psi peak overpressure to model repeated mild blast traumatic brain injury (rmbTBI) in rats followed by assessment of mitochondrial respiration and mitochondrial-related oxidative damage at 2 days post-rmbTBI. Treatment groups were administered 8 or 80 mg/kg MP201, a prodrug of 2,4 dinitrophenol (DNP) that displays improved pharmacokinetics compared with its metabolized form. Synaptic and glia-enriched mitochondria were isolated using fractionated a mitochondrial magnetic separation technique. There was a consistent physiological response, decreased heart rate, following mbTBI among experimental groups. Although there was a lack of injury effect in mitochondrial respiration of glia-enriched mitochondria, there were impairments in mitochondrial respiration in synaptic mitochondria isolated from the prefrontal cortex (PFC) and the amygdala/entorhinal/piriform cortex (AEP) region. Impairments in synaptic mitochondrial respiration were rescued by oral 80 mg/kg MP201 treatment after rmbTBI, which may be facilitated by increases in complex II and complex IV activity. Mitochondrial oxidative damage in glia-enriched mitochondria was increased in the PFC and hippocampus after rmbTBI. MP201 treatment alleviated elevated glia-enriched mitochondrial oxidative damage following rmbTBI. However, there was a lack of injury-associated differences in oxidative damage in synaptic mitochondria. Overall, our report demonstrates that rmbTBI results in mitochondrial impairment diffusely throughout the brain and mild mitochondrial uncoupling can restore mitochondrial bioenergetics and oxidative balance.

Modeling of hydrogen dispersion and explosion of a fuel cell vehicle in an underground parking garage

Numerical simulations were conducted to investigate the hydrogen dispersion and deflagration in an underground garage, considering potential leaks from hydrogen fuel cell vehicles. This study constructed a geometric model based on vehicles equipped with 70 MPa hydrogen tanks and considered various accident scenarios by adjusting the orifice diameter and ignition time. The results indicated that the peak overpressure was influenced by the equivalence ratio, hydrogen distribution and ignition time. Specifically, increasing orifice diameter led to greater overpressure when ignition occurred 0.1 s after release, while the opposite trend was observed for ignition at 1 s or 10 s. Temperature and overpressure were measured to evaluate the hazard distances, revealing inconsistencies between distances determined by pressure and temperature, with the latter yielding larger results. This research contributes to determining affected areas and safety distances in hydrogen accidents, provides references for the design of parking intervals and the development of emergency plans.

Assessment of modeling methods for predicting load resulting from hydrogen-air detonation

As hydrogen becomes an increasingly vital component in the transition toward a sustainable energy system, its flammable and detonable properties necessitate a comprehensive understanding of its explosive characteristics. This study evaluated the accuracy and computational efficiency of an innovative numerical approach that integrates CESE compressible CFD solver, chemistry reaction model, and structural FEM solver within LS-DYNA to predict hydrogen detonation loads. Comparisons were made with the commonly used energy equivalent methods, i.e., the TNT equivalent method, and the high-pressure volume method, which utilizes multi-material ALE techniques. Hydrogen detonation test results from open-air space, open-air space with a blast wall, and semi-confined space were compared against numerical simulations. The results revealed that, for scaled distance exceeding 0.79 m/kg1/3, all three methods accurately predicted the peak overpressure. The TNT equivalent method exhibited an unexpectedly high energy efficiency factor exceeding 0.51, significantly surpassing the recommended range of 0.01–0.1 for typical vapor cloud accidents. The CESE-chemistry coupling method exceled in capturing overpressure duration and structural response due to its consideration of chemical kinetics. As the scaled distance reduced to 0.37 m/kg1/3, the CESE-chemistry coupling method maintained its proficiency in modelling pressure waves, while the TNT equivalent method overestimated peak pressure by 494%. Conversely, the high-pressure volume method underestimated the peak pressures within or near the H2-air cloud. Nevertheless, the CESE-chemistry coupling method required significantly higher computational costs, with 15–20 times more computational time compared to the other two methods, and 60–70% of the total computation time was spent solving chemical kinetics. It is concluded from the current study that for scenarios involving close scaled distances (less than 0.37 m/kg1/3) or where the structure locates inside or near the gas cloud, the CESE-chemistry coupling method may be preferred despite its higher computational demands. Conversely, for simulations prioritizing computational efficiency and larger scaled distances, the TNT equivalent method or high-pressure volume method is recommended. These findings offer guidelines for researchers and engineering professionals engaged in assessing and mitigating risks associated with hydrogen explosion accidents in the pursuit of safe and sustainable hydrogen utilization.

Evaluation of blast wave from hydrogen pipeline burst by a coupled fluid-structure-rupture approach

Coupled fluid-structure-rupture model was developed to evaluate the blast field from X65 hydrogen pipeline burst. Johnson-Cook material model was implemented considering the high strain rates of material at crack tips. Internal hydrogen decompression, outer blast wave generation and propagation, and dynamic rupture of pipeline were simulated simultaneously and validated with experiments. Results demonstrated that the crack primarily ran axially at an average speed of about 120 m/s, while the maximum speed was about 200 m/s. Due to the dynamic growth of rupture opening, the outer blast wave experienced a process of first form and then strengthened by subsequent compression waves. This makes the maximum peak overpressure along the jetting direction appears at a certain standoff distance above rupture. The blast overpressures along the jetting direction were compared and discussed with those from traditional CFD method, TNT equivalence method and Baker-Tang blast curves. It was found the effective volume to calculate the burst energy needs to be further studied. Also, new blast curves were required for quick and rational estimation of blast overpressure from hydrogen pipeline burst.

Scaling law of deep-sea trinitrotoluene (TNT) explosion

Understanding the dynamic characteristics of deep-sea explosions is essential to improve the survivability and combat capability of deep-sea equipment. In this paper, by considering the practical underwater conditions, we investigated the mechanical effects of the deep-sea 1-kg-trinitrotoluene (TNT) explosion with charge depths ranging from 1 to 10 km through numerical simulation and dimensional analysis. The shock wave overpressure, the positive overpressure pulse, the bubble pulse, and the energy distribution for various depth explosions were analyzed systematically. The simulation results showed that the charge depth was negligible for the peak overpressure of the shock wave. However, the positive overpressure pulse, the shock wave energy, the maximum bubble radius, the bubble energy, and the bubble period decrease significantly with increasing the charge depth. Then, the dimensional analysis for deep-sea TNT explosion was performed to reveal the key dimensionless parameters, from which the scaling laws of the shock wave overpressure and the overpressure pulse were obtained. By fitting the simulation results, the dimensionless equations were proposed, providing an effective method for predicting the peak overpressure and the positive overpressure pulse of shock wave for underwater TNT explosion over a wide range of water depths.

A Database Extension for a Safety Evaluation of a Hydrogen Refueling Station with a Barrier Using a CFD Analysis and a Machine Learning Method

A methodology is proposed to extend datasets in a database suitable for use as a reference tool to support an evaluation of damage mitigation by a barrier wall in a hydrogen refueling station (HRS) during a vapor cloud explosion (VCE) accident. This is realized with a computational fluid dynamic (CFD) analysis and machine learning (ML) technology because measured data from hydrogen explosion tests with various installed barrier models usually require considerable amounts of time, a secured space, and precise measurements. A CFD sensitivity calculation was conducted using the radXiFoam v1.0 code and the established analysis methodology with an error range of approximately ±30% while changing the barrier height from that was used in an experiment conducted by the Stanford Research Institute (SRI) to investigate the effect of the barrier height on the reduction in peak overpressures from an explosion site to far fields in an open space. The radXiFoam code was developed based on the open-source CFD software OpenFOAM-v2112 to simulate a VCE accident in a humid air environment at a compressed gaseous or liquefied HRS. We attempted to extend the number of datasets in the VCE database through the use of the ML method on the basis of pressure data predicted by a CFD sensitivity calculation, also uncovering the possibility of utilizing the ML method to extend the VCE database. The data produced by the CFD sensitivity calculation and the ML method will be examined to confirm their validity and applicability to hypothetical VCE accident simulations if the related test data can be produced during experimental research. The database constructed using core data from the experiment and extended data from the CFD analysis and the ML method will be used to increase the credibility of radXiFoam analysis results for VCE accident scenarios at HRSs, ultimately contributing to safety assurances of HRSs in Republic of Korea.

Experimental study on combustion of H2–CO–air mixtures in closed and vented vessels

Experiments were conducted in two test facilities, a 0.25 m3 spherical vessel and a 60 m3 rectangular vented chamber, to examine the premixed combustion behavior of H2–CO mixtures. The study aims to provide data for the validation of models used for the assessment of combustion risks during postulated nuclear severe accidents and the use of syngas as an alternative fuel. The effects of fuel concentrations, molar ratio of CO/H2, initial gas temperature, steam concentration, and fan-induced turbulence on the flame dynamics are presented in this paper. The measurements are compared with literature data and predictions by empirical correlations. Within the range of the fuel concentration (≤15% in air) examined in this study, the results demonstrate that both the closed and vented combustion dynamics of H2–CO–air mixtures are similar to those of H2 only mixtures. The peak overpressures are always greater with more H2 in the mixture due to slower flame speeds of CO relative to H2. The combustion overpressures of H2–CO mixtures become similar to those of H2 mixtures when the fuel concentration is greater than what is required for downward flame propagation. The effect of fan-induced turbulence is much more pronounced for extremely lean mixtures.

Numerical analysis of the effect of ventilation door on the propagation characteristics of gas explosion shock waves

Ventilation door are commonly found in tunnels and other underground engineering ventilation structures, disaster periods using its explosion isolation, explosion relief, wind regulation characteristics for disaster prevention and mitigation is of great significance. This paper numerically simulates the propagation characteristics of the gas explosion shock wave in the nearby tunnel when the ventilation door are opened at different degrees, and analyzes the influence mechanism of the opening degree on the change law of the shock wave overpressure distribution in the nearby tunnel. The results show that the shock wave forms a strong turbulence area (high pressure area) on both sides in front of the ventilation door, and the area range and the overpressure value decrease with the increase of the opening degree; the ventilation door reduce the intensity of the shock wave, so that the overpressure behind the ventilation door decreases, and the smaller the opening degree, the lower the overpressure behind the ventilation door. The secondary explosion formed shock wave and the ventilation door reflected shock wave meet to form a stronger shock wave, which leads to different opening degrees of ventilation door, its before, after the roadway and after the bifurcation of the main roadway in the measured points of the overpressure change curve is different, the main difference is that the peak overpressure for the first wave or the second wave peak. The peak overpressure in the tunnel before and after the ventilation door decreases and increases respectively with the increase of the opening length, and the overall decay of the peak overpressure at 5 m and 10 m before the ventilation door is 49.56% and 4.04% respectively and only has an effect on the peak overpressure in main tunnel within 20 m from the bifurcation.

Magmatic volatile content and the overpressure ‘sweet spot’: Implications for volcanic eruption triggering and style

Volatile exsolution is widely considered to be capable of generating magmatic overpressure and triggering volcanic eruptions. Despite its role as an eruption trigger, exsolution-driven overpressurisation is relatively poorly understood. Part of the problem is that thermodynamic models do not consider how the behaviour of small quantities of magma scales up to reservoir level – where variations in temperature and crystallinity become important. In contrast, many thermomechanical models focus only on magma injection, and do not consider how overpressure evolves spatially or temporally, when related to crystallisation and volatile exsolution. Here, we use Rhyolite-MELTS to track exsolution-driven overpressure during cooling for a variety of natural compositions, storage pressures, initial volatile contents and magmatic XH2O (molar H2O/ (CO2 + H2O)). We then couple these outputs to a thermal model to determine the timescales and spatial extent of overpressurisation with varying volatile content.We find that the highest overpressures occur in magmas which are initially at their H2O solubility limit, with the addition or removal of H2O resulting in a decrease in peak overpressure. We also find that maximum overpressure decreases with the addition of CO2 (decreasing XH2O) at typical magma storage pressures of 100–230 MPa. The higher overpressures generated at the volatile ‘sweet spot’ have a greater potential to trigger eruptions – or to favour their initiation by making the system more susceptible to other triggers, such as magma injection. The reduction in overpressure with increasing or decreasing initial H2O suggests that triggering by volatile exsolution is less likely for these magmas. Peak overpressure at the volatile sweet spot also coincides with an increased incidence of explosive eruptions at water contents ∼4–5.5 wt%. This suggests that higher magmatic overpressures may produce more explosive eruptions, by driving faster initial ascent rates and decreasing outgassing efficiency in the conduit. Our thermal modelling demonstrates that, for small magmatic systems, exsolution-driven overpressurisation can operate on timescales which are much shorter than the crustal relaxation timescale. In these cases, overpressure cannot be dissipated by a visco-elastic crustal response, and therefore has the potential to trigger a volcanic eruption.

Study on effect of transverse concentration gradients in pipeline on methane explosion characteristics

In this paper, we studied the effects of transverse concentration gradients on methane explosion characteristics using a fully-transparent pipeline and finally came to the following conclusions. The peak explosion overpressure changed in a waveform of “M” along different measuring points, but a set of non-equivalent concentration gradients maximized this peak value. Higher methane concentrations in the Q2 region could cause the secondary peak overpressure near the both ends of the pipe. In this process, the flame outside the pipe tends to form a near-spherical shape. However, at lower methane concentrations in the Q2 region, the secondary peak overpressure was only detected near the outlet. Its occurrence at different sites may relate to the turbulence effect heightened by concentration gradients. Besides, under the same gradient, the smallest propagation speed was measured on the right of the ignition source when the flame propagated fastest on the left, which was attributed to different inhibiting effects of reflected waves on flame propagation.

Layout considerations on compound survival shelters for blast mitigation: A finite-element approach

The safety of both military personnel and equipment in unstable regions has for a long time been a major issue and concern. Protective shelters with multiple configurations have been widely used to meet safety requirements. Since military compounds are subjected to different types of threats, such as the detonation of improvised explosive devices (IED), a good understanding of the response of such shielding structures to blast waves is critical. A three-dimensional finite element (FE) model of a corner-entry ISO 20 ft container HESCO-Bastion survival shelter is developed, validated and tested under the external detonation of explosive charges. The FE model is validated against experimental data and used to investigate the protective performance of the shelter by considering several design-related parameters, such as charge location, roof extension, interior corridor dimensions and the effect of venting and its location. Results are discussed in terms of peak overpressure and maximum impulse at discrete locations around the container, and it is found that the shelter is the least efficient in mitigating the blast load propagation when the explosive material is at an angle of 45° to the entrance. Also, while the protective roof at the entrance plays a significant role in protecting the container from air-borne threats, it is observed that it contributes to higher pressure and impulse data within the shelter, for detonations at ground level, with impulse amplifications as high as 94% when fully covering the entrance area. Contrarily, varying the distance between the container and the HESCO-Bastions is found to have minimal impact on the impulse, while naturally decreasing the peak pressure for increasing distances. Venting (through openings) can lead to up to 95% reduction in the peak pressure, whilst not affecting the impulse.

Effects of hydrogen addition on the explosion venting characteristics of hydrogen-propane-air mixtures

To study the effect of hydrogen fraction (η) in stoichiometric hydrogen-propane-air mixtures ranging from 0 to 1.0 on overpressure and external flame temperature, experiments on the vented explosion are conducted in a 1-m long cylindrical tube with a vent on the top surface. The explosion venting process is recorded by the high-speed shadowgraph imaging system, pressure testing system, and infrared thermal imager. The internal peak overpressure is proportional to the hydrogen fraction, and the external pressure peak (PExt) induced by the second explosion in the external flow field shows a similar trend. The higher external impulse occurs in higher hydrogen fractions and farther distances. The maximum flame length drops first and then rises with the addition of η. The maximum surface temperature of the external flame peaks at η = 1, followed by that of η = 0, η = 0.3, η = 0.9, and η = 0.6, respectively. Besides, the relative-safety radii, free of thermal radiant damage, are obtained.

Propagation of the blast wave in the enclosed blast wall structure (EBWS) at a hazardous chemical storage yard—A mechanism study

The storage and transportation of hazardous chemicals is an essential aspect of modern economic activities. The explosion of hazardous chemicals can cause significant damage to surrounding infrastructure and human life, and has become a major public concern. The enclosed blast wall structure (EBWS) is commonly used in open-air storage yards to segregate explosion hazards. However, the understanding of blast wave propagation in an EBWS is limited. In this study, the propagation of blast waves in an EBWS at a hazardous chemical storage yard was analyzed through a combination of scaled field tests and numerical simulations. The study focuses on reflection and diffraction effects in the access passage, which is connected to the opening of the EBWS for transportation purposes. A decoupling technique was proposed to evaluate the contribution of blast waves propagating through the entrance of the access passage and diffracting from above the blast wall separately. Several special wave propagation effects in EBWS were identified, such as leakage pressure and oblique incidence. The blast load experienced in the access passage were compared with current codes and prediction methods. It was found that the commonly adopted assumptions of a semi-infinite blast wall and normal incidence of blast waves underestimates the peak overpressure in the access passage and could not predict the following multiple overpressure peaks. Finally, a calculation procedure based on the TNT equivalent was proposed to predict the overpressure behind the blast wall with a slant angle.

Experimental and finite element analysis of the generation mechanism of high impulse noise overpressure (caused by a recoilless weapon) at the bottom of the ear

The intense impulse noise may damage the soldiers’ hearing organs during a weapon's firing. It is essential to find out the generation mechanism of the overpressure at the bottom of the ear. The experiments of measuring the overpressure at the bottom of the ear were conducted through a rotating human head model at a recoilless weapon firing platform. The results showed that the overpressure peak at the bottom of the ear decreases with the increasing incident angle. A simulation of the test condition was developed based on the plane shock wave method. The finite element model was verified reasonably compared to the test results. The Friedlander wave propagating to the ear canal was implemented at different incident angles. The generation of the overpressure at the bottom of the ear was analyzed. According to the pressure nephograms, the impulse noise stagnated at the bottom of the ear, so the overpressure was the total pressure of impulse noise. Two parts of impulse noise entered the canal successively due to the influence of the pinna. The overpressure and Mach number at the entrance of the ear canal both decreased with increasing incident angles, resulting in impulse noise superimposed at the bottom of the ear. Investigating the generation of overpressure at the bottom of the ear under varying incident angles may have important reference value for analyzing and preventing auditory organ damage caused by impulse noise.