Wave Overpressure Research Articles

Chapter 2 traumatic brain injury research in military populations.

Traumatic brain injury (TBI) in all of its forms--blast, concussive, and penetrating--has been an unfortunate sequela of warfare since ancient times. The continued evolution of military munitions and armor on the battlefield, as well as the insurgent use of improvised explosive devices, has led to blast-related TBI whose long-term effects on behavior and cognition are not yet known. Advances in medical care have greatly increased survival from these types of injuries. Therefore, an understanding of the potential health effects of TBI is essential. This review focuses on specific aspects of military-related TBI. There exists a large body of literature reporting the environmental conditions, forces, and staging of injury. Many of these studies are focused on the neuropathology of TBI, due to blast overpressure waves, and the emergence of large numbers of mild blast-related TBI cases.

Explosion impacts during transport of hazardous cargo: GIS-based characterization of overpressure impacts and delineation of flammable zones for ammonia

The aim of this research was to investigate accidental releases of ammonia followed by an en-route incident in an attempt to further predict the consequences of hazardous cargo accidents. The air dispersion model Areal Locations of Hazardous Atmospheres (ALOHA) was employed to track the probable outcomes of a hazardous material release of a tanker truck under different explosion scenarios. The significance of identification of the flammable zones was taken into consideration; in case the flammable vapor causes an explosion. The impacted areas and the severity of the probable destructions were evaluated for an explosion by considering the overpressure waves. ALOHA in conjunction with ArcGIS was used to delineate the flammable and overpressure impact zones for different scenarios. Based on the results, flammable fumes were formed in oval shapes having a chief axis along the wind direction at the time of release. The expansions of the impact areas under the overpressure value which can lead to property damage for 2 and 20 tons releases, under very stable and unstable atmospheric conditions were estimated to be around 1708, 1206; 3742, 3527 feet, respectively, toward the wind direction. A sensitivity analysis was done to assess the significance of wind speed on the impact zones. The insight provided by this study can be utilized by decision makers in transportation of hazardous materials as a guide for possible rerouting, rescheduling, or limiting the quantity of hazardous cargo to reduce the possible impacts after hazardous cargo accidents during transport.

Mitigation of Solid Booster Ignition over Pressure by Water Aerosol Sprays

Interaction of acoustic waves with water aerosol layers is analyzed in the context of the problem of solid booster ignition overpressure suppression. In contrast to the conventional approach to ignition overpressure suppression, which aims at using water to quench the sources of the ignition overpressure waves, this study focuses on blocking the ignition overpressure wave propagation, using reflection and attenuation of the wave by the water aerosol layers. The study considers interaction of the waves with aerosol layers of large mass loading for varying sizes of the droplets. The size of the droplets is shown to substantially affect the mechanisms of interaction with the waves. The criteria for the crossover between different mechanisms are established as functions of the droplet size and the ignition overpressure wave parameters. The optimal parameters and designs for water aerosol sprays are proposed that maximize the ignition overpressure suppression. These results were obtained using the nozzle and the exhaust hole geometries similar to those of the space shuttle. Remarkably, it is found that various a priori reasonable designs of the aerosol and water sprays may increase the ignition overpressure impact on the vehicle, increasing the risk of vehicle damage.

Pressure and flow propagation rule beyond original premixed area of methane-air in tunnel

Purpose – Whether a fire can be initiated in an explosion accident depends on the explosion and deflagration process. In the methane-air explosion in a tunnel, the flame accelerates from the ignition point. However, where it begins to decelerate is not clear. The purpose of this paper is to examine the explosion overpressure, flow and flame propagation beyond the premixed area of methane-air in a tunnel. Design/methodology/approach – The numerical simulation was used to study the explosion processes of methane-air mixtures in a tunnel. Based on the numerical simulation and its analysis, the explosion overpressure, flow and flame propagation rules beyond the premixed area were demonstrated for a methane-air explosion. Findings – The peak overpressure of methane-air mixture explosion was observed to reach its maximum beyond the original premixed area of methane-air. The hazardous effects beyond the premixed area may be stronger than those within the premixed area for a methane-air explosion in a tunnel. Under the conditions of this study, the ratio between the length of combustion area (40 m) and that of original premixed area (28 m) reaches 1.43. Originality/value – Little attention has been devoted to investigating the explosion overpressure, flow and flam propagations beyond the original premixed area of methane-air in a tunnel. Based on the numerical simulation and the analysis, the propagation rule of overpressure wave and flow inside and outside the space occupied by methane/air mixture at the volume fraction of 9.5 percent in a tunnel were obtained in this work.

Acoustic signature characterization of a sub-scale rocket launch

Georgia Tech Research Institute (GTRI) conducted a flight test of a sub-scale rocket in 2013 outside Talladega, Alabama, to acquire the launch acoustics produced. The primary objective of the test was to characterize the acquired data during a sub-scale launch and compare it with heritage launch data from the STS-1 Space Shuttle flight. Neither launch included acoustic suppression; however, there were differences in the ground geometry. STS-1 launched from the Mobile Launch Platform at Pad 39B with the RS-25 liquid engines and Solid Rocket Boosters (SRBs) firing into their respective exhaust ducts and flame trench, while the GTRI flight test vehicle launched from a flat reflective surface. The GTRI launch vehicle used a properly scaled Solid Rocket Motor (SRM) for propellant; therefore, primary analysis will focus on SRM/SRB centric acoustic events. Differences in the Ignition Overpressure (IOP) wave signature between both due to this will be addressed. Additionally, the classic liftoff acoustics “football shape” is preserved between both full and sub-scale flights. The launch signatures will be compared, with note taken of specific launch acoustic events more easily investigated with sub-scale launch data or supplement current sub-scale static hotfire testing.

From battleside to stateside: the reconstructive journey of our wounded warriors.

Recent military operations in Iraq (Operation Iraqi Freedom) and Afghanistan (Operation Enduring Freedom) have led to further refinements of the military medical system's ability to provide advanced surgical care. The deployment of a global trauma care system has directly contributed to improved combat casualty survival rates. As a consequence of improved survivorship, a high-volume patient population of individuals having challenging multiple extremity injuries/amputations has presented to military treatment facilities. These patients present with unique mixed pattern blast injuries. Blast injuries incorporate multiple mechanisms of injury including penetrating fragmentary injury, blunt force trauma, flash burn, and overpressure wave damage. These complex injuries have furthered refinements in traditional reconstruction and facilitated early application of regenerative medicine therapies. This article summarizes information presented at the inaugural Garry Brody, MD Family Invited Lectureship presented at the 63rd California Society of Plastic Surgeons Annual.

Numerical Study of Solid-Rocket Motor Ignition Overpressure Wave Including Infrared Radiation

The ignition overpressure wave generated during the pressure build-up of a solid-rocket motor is numerically investigated in this study. Numerical simulations are compared to the LP10 experiments, consisting of the horizontal firing of a scaled-down model for the Ariane 5 P230 booster. The present work aims at the prediction of the main characteristics of the ignition overpressure in the far field and the assessment of afterburning influence on both its formation mechanisms and its alteration by the jet plume. Two three-dimensional large-eddy simulations are performed, one considering inert flow and one modeling the afterburning. Infrared images of the plume are also computed with a dedicated radiation transfer solver. An overall good agreement with the experimental results is reported on amplitude and duration. Nevertheless, the reactive case is found to provide better results on amplitude and directivity. The signature is also better reproduced on the microphones near the jet centerline, and the emitted infrared intensity is well captured. Computations indicate that the formation of the shock wave is obtained by coalescence of compression waves emitted by the accelerating jet at early times. For the reactive case, computations show an increased interaction between the jet and the overpressure wave.

Overpressure blast-wave induced brain injury elevates oxidative stress in the hypothalamus and catecholamine biosynthesis in the rat adrenal medulla

Explosive overpressure brain injury (OBI) impacts the lives of both military and civilian population. We hypothesize that a single exposure to OBI results in increased hypothalamic expression of oxidative stress and activation of the sympatho-adrenal medullary axis. Since a key component of blast-induced organ injury is the primary overpressure wave, we assessed selective biochemical markers of autonomic function and oxidative stress in male Sprague Dawley rats subjected to head-directed overpressure insult. Rats were subjected to single head-directed OBI with a 358kPa peak overpressure at the target. Control rats were exposed to just noise signal being placed at ~2m distance from the shock tube nozzle. Sympathetic nervous system activation of the adrenal medullae (AM) was evaluated at 6h following blast injury by assessing the expression of catecholamine biosynthesizing enzymes, tyrosine hydroxylase (TH), dopamine-β hydroxylase (DβH), neuropeptide Y (NPY) along with plasma norepinephrine (NE). TH, DβH and NPY expression increased 20%, 25%, and 91% respectively, following OBI (P<0.05). Plasma NE was also significantly elevated by 23% (P<0.05) following OBI. OBI significantly elevated TH (49%, P<0.05) in the nucleus tractus solitarius (NTS) of the brain stem while AT1 receptor expression and NADPH oxidase activity, a marker of oxidative stress, was elevated in the hypothalamus following OBI. Collectively, the increased levels of TH, DβH and NPY expression in the rat AM, elevated TH in NTS along with increased plasma NE suggest that single OBI exposure results in increased sympathoexcitation. The mechanism may involve the elevated AT1 receptor expression and NADPH oxidase levels in the hypothalamus. Taken together, such effects may be important factors contributing to pathology of brain injury and autonomic dysfunction associated with the clinical profile of patients following OBI.

Experimental Animal Models for Studies on the Mechanisms of Blast-Induced Neurotrauma

A blast injury is a complex type of physical trauma resulting from the detonation of explosive compounds and has become an important issue due to the use of improvised explosive devices (IED) in current military conflicts. Blast-induced neurotrauma (BINT) is a major concern in contemporary military medicine and includes a variety of injuries that range from mild to lethal. Extreme forces and their complex propagation characterize BINT. Modern body protection and the development of armored military vehicles can be assumed to have changed the outcome of BINT. Primary blast injuries are caused by overpressure waves whereas secondary, tertiary, and quaternary blast injuries can have more varied origins such as the impact of fragments, abnormal movements, or heat. The characteristics of the blast wave can be assumed to be significantly different in open field detonations compared to explosions in a confined space, such an armored vehicle. Important parameters include peak pressure, duration, and shape of the pulse. Reflections from walls and armor can make the prediction of effects in individual cases very complex. Epidemiological data do not contain information of the comparative importance of the different blast mechanisms. It is therefore important to generate data in carefully designed animal models. Such models can be selective reproductions of a primary blast, penetrating injuries from fragments, acceleration movements, or combinations of such mechanisms. It is of crucial importance that the physical parameters of the employed models are well characterized so that the experiments can be reproduced in different laboratory settings. Ideally, pressure recordings should be calibrated by using the same equipment in several laboratories. With carefully designed models and thoroughly evaluated animal data it should be possible to achieve a translation of data between animal and clinical data. Imaging and computer simulation represent a possible link between experiments and studies of human cases. However, in order for mathematical simulations to be completely useful, the predictions will most likely have to be validated by detailed data from animal experiments. Some aspects of BINT can conceivably be studied in vitro. However, factors such as systemic response, brain edema, inflammation, vasospasm, or changes in synaptic transmission and behavior must be evaluated in experimental animals. Against this background, it is necessary that such animal experiments are carefully developed imitations of actual components in the blast injury. This paper describes and discusses examples of different designs of experimental models relevant to BINT.

Clinical relevance of blast-related traumatic brain injury

The global war against terrorism has created new challenges for neurosurgeons, craniofacial surgeons and maxillofacial surgeons; United States military operations in Iraq and Afghanistan have resulted in the greatest incidence of head trauma since the Vietnam conflict. The more frequent use of improvised explosive devices (IED), in conjunction with increased survival from improved body armor and battlefield medicine, has contributed to the increasing number of craniomaxillofacial injuries and consequent head trauma [28]. IEDs usually contain an explosive that, during detonation, is converted into a gas that rapidly expands and forms a high-pressure wave [4]. This blast overpressure wave travels at supersonic speeds and causes primary blast injury. The subsequent blast wind that follows the initial blast wave can propel objects, leading to further harm [7, 29]. The effect of a primary blast wave on the brain remains poorly understood despite the various models and computer simulations used to predict different mechanisms of injury [5, 27]. Because 59% of the service members in Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) suffered from TBI [21], a better understanding of mechanisms underlying primary blast injury and the establishment of guidelines of care are warranted. Persistent and debilitating symptoms are often associated with mild traumatic brain injury [24], underscoring the need for improved diagnostic and therapeutic modalities. Diffuse axonal injury (DAI) is widely hypothesized to be a principle mechanism of damage and the cause of persistent cognitive defects after traumatic brain injury (TBI). Angular forces can cause shearing or stretching of axons, leading to impaired axonal transport and swelling [9]. However, further elucidation of the pathological mechanism behind blast injury and determining the ideal diagnostic method to identify this condition may help lead to greater protection for military personnel and treatments for those already suffering from this disease. The majority (85%) of reported TBI cases are undetectable with imaging (computed tomography (CT) and magnetic resonance imaging (MRI) are usually insensitive to its characteristic small lesions [1, 13]) and are classified as mild [2, 25] based on the Department of Defense (DoD) screening criteria. The DoD defines mild TBI as loss of consciousness, amnesia, mental status alteration at time of injury, and/or focal neurological deficit or peri-injury confusion/disorientation in a patient with a Glasgow Coma Scale (GCS) score of 13–15 [18]. Once diagnosed, mild TBI is a treatable disease typically associated with a very favorable prognosis [15]. As a result, the recently published results by Mac Donald and colleagues have created a sense of cautious optimism regarding the use of diffusion tensor imaging (DTI) in detecting structural brain damage in blast-exposed patients suffering from mild TBI. In their study, Mac Donald et al. enrolled 63 patients, ages 19–58, from a screened population of 122 service members. The primary goal was to establish whether or not traumatic axonal injury is a primary feature of human blastG. Appelboom : J. Han : S. Bruce : E. S. Connolly Jr. Department of Neurological Surgery, The Neurological Institute, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA

5% Ares I scale model acoustic test: Overpressure characterization and analysis

During the ignition of a ducted solid rocket motor (SRM), rapid expansion of injected hot gases from the motor into a confined volume causes the development of a steep fronted wave. This low frequency transient wave propagates outward from the exhaust duct, impinging the vehicle and ground structures. An unsuppressed overpressure wave can potentially cause modal excitation in the structures and vehicle, subsequently leading to damage. This presentation details the ignition transient findings from the 5% Ares I scale model acoustic test (ASMAT). The primary events of the ignition transient environment induced by the SRM are the ignition overpressure (IOP), duct overpressure (DOP), and source overpressure (SOP). The resulting observations include successful knockdown of the IOP environment through use of a space shuttle derived IOP suppression system, a potential load applied to the vehicle stemming from instantaneous asymmetrical IOP and DOP wave impingement, and launch complex geometric influences on the environment. The results are scaled to a full-scale Ares I equivalent and compared with heritage data including Ares I-X and both suppressed and unsuppressed space shuttle IOP environments.

Mass accretion to young stars triggered by flaring activity in circumstellar discs

Young low-mass stars are characterized by ejection of collimated outflows and by circumstellar disks which they interact with through accretion of mass. The accretion builds up the star to its final mass and is also believed to power the mass outflows, which may in turn remove the excess angular momentum from the star-disk system. However, although the process of mass accretion is a critical aspect of star formation, some of its mechanisms are still to be fully understood. A point not considered to date and relevant for the accretion process is the evidence of very energetic and frequent flaring events in these stars. Flares may easily perturb the stability of the disks, thus influencing the transport of mass and angular momentum. Here we report on three-dimensional magnetohydrodynamic modeling of the evolution of a flare with an idealized non--equilibrium initial condition occurring near the disk around a rotating magnetized star. The model takes into account the stellar magnetic field, the gravitational force, the viscosity of the disk, the magnetic-field-oriented thermal conduction (including the effects of heat flux saturation), the radiative losses from optically thin plasma, and the coronal heating. We show that, during its first stage of evolution, the flare gives rise to a hot magnetic loop linking the disk to the star. The disk is strongly perturbed by the flare: disk material evaporates under the effect of the thermal conduction and an overpressure wave propagates through the disk. When the overpressure reaches the opposite side of the disk, a funnel flow starts to develop there, accreting substantial disk material onto the young star from the side of the disk opposite to the flare.

Survival Risk Assessment for Primary Blast Exposures to the Head

Many soldiers returning from the current conflicts in Iraq and Afghanistan have had at least one exposure to an explosive event and a significant number have symptoms consistent with traumatic brain injury. Although blast injury risk functions have been determined and validated for pulmonary injury, there is little information on the blast levels necessary to cause blast brain injury. Anesthetized male New Zealand White rabbits were exposed to varying levels of shock tube blast exposure focused on the head, while their thoraces were protected. The specimens were euthanized and evaluated when the blast resulted in respiratory arrest that was non-responsive to resuscitation or at 4?h post-exposure. Injury was evaluated by gross examination and histological evaluation. The fatality data from brain injury were then analyzed using Fisher's exact test to determine a brain fatality risk function. Greater blast intensity was associated with post-blast apnea and the need for mechanical ventilation. Gross examination revealed multifocal subdural hemorrhages, most often near the brainstem, at more intense levels of exposure. Histological evaluation revealed subdural and subarachnoid hemorrhages in the non-responsive respiratory-arrested specimens. A fatality risk function from blast exposure to the head was determined for the rabbit specimens with an LD(50) at a peak overpressure of 750?kPa. Scaling techniques were used to predict injury risk at other blast overpressure/duration combinations. The fatality risk function showed that the blast level needed to cause fatality from an overpressure wave exposure to the head was greater than the peak overpressure needed to cause fatality from pulmonary injury. This risk function can be used to guide future research for blast brain injury by providing a realistic fatality risk to guide the design of protection or to evaluate injury.

A Mouse Model of Blast Injury to Brain: Initial Pathological, Neuropathological, and Behavioral Characterization

The increased use of explosives in recent wars has increased the number of veterans with blast injuries. Of particular interest is blast injury to the brain, and a key question is whether the primary overpressure wave of the blast is injurious or whether brain injury from blast is mostly due to secondary and tertiary effects. Using a shock tube generating shock waves comparable to open-field blast waves, we explored the effects of blast on parenchymatous organs of mice with emphasis on the brain. The main injuries in nonbrain organs were hemorrhages in the lung interstitium and alveolar spaces and hemorrhagic infarcts in liver, spleen, and kidney. Neuropathological and behavioral outcomes of blast were studied at mild blast intensity, that is, 68 ± 8 kPag (9.9 ± 1.2 psig) static pressure, 103 kPag (14.9 psig) total pressure and 183 ± 14 kPag (26.5 ± 2.1 psig) membrane rupture pressure. Under these conditions, we observed multifocal axonal injury, primarily in the cerebellum/brainstem, the corticospinal system, and the optic tract. We also found prolonged behavioral and motor abnormalities, including deficits in social recognition and spatial memory and in motor coordination. Shielding of the torso ameliorated axonal injury and behavioral deficits. These findings indicate that long CNS axon tracts are particularly vulnerable to the effects of blast, even at mild intensities that match the exposure of most veterans in recent wars. Prevention of some of these neurological effects by torso shielding may generate new ideas as to how to protect military and civilian populations in blast scenarios.

Molecular Dynamic Simulations of Blast Waves on Bilayers

Many studies using animal models have shown that blast waves cause injuries to the brain despite the lack of a direct physical impact to the brain or skull. Such injuries are manifested as biochemical, functional, or morphological alterations that result in motor and sensory deficits in addition to behavioral changes. Primary blast due to explosions causes an intense rise of atmospheric pressure, the positive phase, followed by a broader under-pressure, the negative phase. The peak overpressure reaches pressures up to 1724 kPa and the blast wave travels at speeds up to 670 m/s. Because of this high velocity, it is difficult to study the interaction of explosive blast waves with neural tissue in real time. Accordingly, we have performed molecular dynamic (MD) simulations of blast waves on myelin membranes to understand how blast waves interact with neural tissue to cause injury. In our simulations, we have created blast overpressure using a planar wall, which exerts a forces of -K(x0 - x)2; where K is the spring force constant, and x0 and x are the starting and final positions of the wall, respectively. The intensity of the overpressure wave is controlled by the spring stiffness (K) and the duration of the wave is controlled by how far the wall moves (x0 - x). Our findings demonstrate that the velocity of the blast wave is more deleterious to membranes than is the blast overpressure. At velocities above 600 m/s the negative phase can cause bilayers containing phospholipid and cholesterol to bifurcate at the bilayer center. Such structural perturbations could result in diffuse axonal injury, which is believed to play a role in the pathology of blast injury.

A post‐flight ignition overpressure review for the Arex I‐X test rocket.

Ares I‐X post flight ignition overpressure review ignition overpressure (IOP) is an unsteady fluid flow and acoustic phenomena caused by the rapid expansion of gas from the rocket nozzle within a ducted launching space resulting in an initially higher overpressure wave. This wave is potentially dangerous to the structural integrity of the vehicle. An in‐depth look at the IOP environments resulting from the Ares I‐X solid rocket booster configuration showed good correlation between the pre‐flight predictions and post‐flight analysis results. Correlation between the chamber pressure and IOP transients showed successful acoustic mitigation, containing the strongest IOP waves below the mobile launch pad deck. The flight data allowed subsequent verification and validation of Ares I‐X unsteady fluid ducted launcher predictions, computational fluid dynamic models, and strong correlation to historical shuttle data.

Blast‐related mild traumatic brain injury: mechanisms of injury and impact on clinical care

Mild traumatic brain injury has been called the signature injury of the wars in Iraq and Afghanistan. In both theaters of operation, traumatic brain injury has been a significant cause of mortality and morbidity, with blast-related injury the most common cause. Improvised explosive devices have been the major cause of blast injuries. It is estimated that 10% to 20% of veterans returning from these operations have suffered a traumatic brain injury, and there is concern that blast-related injury may produce adverse long-term health affects and affect the resilience and in-theater performance of troops. Blast-related injury occurs through several mechanisms related to the nature of the blast overpressure wave itself as well as secondary and tertiary injuries. Animal studies clearly show that blast overpressure waves are transmitted to the brain and can cause changes that neuropathologically are most similar to diffuse axonal injury. One striking feature of the mild traumatic brain injury cases being seen in veterans of the wars in Iraq and Afghanistan is the high association of mild traumatic brain injury with posttraumatic stress disorder. The overlap in symptoms between the disorders has made distinguishing them clinically challenging. The high rates of mild traumatic brain injury and posttraumatic stress disorder in the current operations are of significant concern for the long-term health of US veterans with associated economic implications.

Study of the Ignition Overpressure Suppression Technique by Water Addition

The main objective of this study is to gain an understanding of the mechanisms responsible for the suppression of the ignition overpressure observed when water is injected through discrete nozzles into a rocket exhaust. A simplified launch-vehicle/launchpad configuration of relevant importance is selected for this study. This configuration is then numerically modeled using two-phase computational fluid dynamics with a representative motor startup sequence and a series of water addition configurations. The study focuses on the interaction between the ignition overpressure wave and the injected water. Chemical reactions are not included in the model; therefore, the effect of afterburning of fuel-rich exhaust is omitted in this study. A total of 11 water addition configurations were studied. The study demonstrated that ignition overpressure is strongly affected by the cooling of the plume and the amount of obstruction restricting the expansion of the plume. Also, the study suggests the existence of an optimal water addition rate with a weak dependence on the water nozzle pressure drop.

Experimentally validated 3-D simulation of shock waves generated by dense explosives in confined complex geometries

Accidental blast wave generation and propagation in the surroundings poses severe threats for people and property. The prediction of overpressure maxima and its change with time at specified distances can lead to useful conclusions in quantitative risk analysis applications. In this paper, the use of a computational fluid dynamics (CFD) code CFX-5.6 on dense explosive detonation events is described. The work deals with the three-dimensional simulation of overpressure wave propagation generated by the detonation of a dense explosive within a small-scale branched tunnel. It also aids at validating the code against published experimental data as well as to study the way that the resulting shock wave propagates in a confined space configuration. Predicted overpressure histories were plotted and compared versus experimental measurements showing a reasonably good agreement. Overpressure maxima and corresponding times were found close to the measured ones confirming that CFDs may constitute a useful tool in explosion hazard assessment procedures. Moreover, it was found that blast wave propagates preserving supersonic speed along the tunnel accompanied by high overpressure levels, and indicating that space confinement favors the formation and maintenance of a shock rather than a weak pressure wave.

Computer simulation of shock waves transmission in obstructed terrains

Abstract Generation and transmission of blast waves in real terrains is of major importance for risk analysis procedures involving accidental explosion scenarios. The problem arises from the impact of overpressure wave on people and structures that may be lethal or catastrophic under certain conditions. In this paper, a CFD simulation of shock wave propagation in obstructed terrain is attempted. Overpressure histories as well as a series of critical parameters, namely the positive and negative peak overpressure, the arrival time, and the positive and negative phase duration at specific points within the domain were obtained during the simulation. Their comparison with experimental measurements from field-scale high explosive blast tests performed by HSE showed a reasonably good agreement indicating that CFD computer programs provide reliable tools for estimating explosive shocks in complex terrains.