Effects Of Shock Waves Research Articles

Comprehensive CFD Analysis of Hypersonic Missile Nose Cone

Abstract: This study employs high-fidelity CFD to analyze a hypersonic missile nose cone's aerodynamics and boundary layer behavior (Mach > 5, zero angles of attack) under idealized conditions. The simulation leverages ideal gas assumptions for simplicity while incorporating advanced turbulence models to capture hypersonic flow phenomena. The analysis focuses on pressure distribution across the nose cone to assess shockwave and streamline curvature effects. Lift and drag forces are computed to evaluate overall aerodynamic performance. Critically, the investigation delves into the boundary layer, evaluating parameters like thickness, velocity profile, and potential separation points to understand pressure and temperature variations crucial for heat transfer and flow stability

Development of a novel method to characterize shock waves interaction with solid objects

Nuclear explosion in a densely populated area is the worst that can happen to any country in the world due to enormous loss of life, property and severe economic damage. Nuclear explosions immediately cause radiological damage and destruction of infrastructure. This hydro-magnetic shock propagation due to blast gives rise to simultaneous signals around the world. The effect of shockwave from nuclear explosion is an area that can be used to handle post and pre-disaster from nuclear explosion. This study focuses on the effects of shockwave on solid objects oriented in different formation. Experiments conducted in a horizontally placed shock tube and a solid object holder on the floor of the test section. These solid objects placed inside the test section of a shock tube collided with a planner shock wave which was generated by rupturing a diaphragm of different thickness. Four high speed pressure transducers strategically placed at different locations of this shock tube were used to characterize the blasts as well as interaction with the samples. A high-speed Kronos and Phantom camera were used to record the exact moment of interaction to characterize the solid objects under the impact of different shock waves. Representative results of these experiments are reported here along with review of previous work done in this area.

Application of extracorporeal shockwave to regulate subchondral bone homeostasis through tumor necrosis factor-α/hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway in treatment of talus bone marrow edema.

To investigate the effect of extracorporeal shock wave on the treatment of talus bone marrow edema by regulating subchondral bone homeostasis through tumor necrosis factor-α (TNF-α)/hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway. A total of 81 patients with talus bone marrow edema admitted to our hospital from May 2019 to May 2021 were studied and divided into control group (n = 40) and extracorporeal shock group (n = 41) according to random number table method. The control group was given conventional treatment, and the extracorporeal shock group was combined with extracorporeal shock wave therapy on the basis of the control group. The expression of TNF-α, HIF-1α, and VEGF in the 2 groups were compared, pain degree, and the area of talus bone marrow edema was evaluated by magnetic resonance imaging. The visual analogue scale scores of 1 month, 2 months and 5 months after treatment were decreased in both groups, and the extracorporeal shock group was lower than the control group (P < .05). After 5 months of treatment, the expressions of TNF-α and HIF-1α were decreased in both groups, and the extracorporeal shock group was lower than the control group, VEGF was increased, and the extracorporeal shock group was higher than the control group (P < .05), and the western blot expression levels of TNF-α, HIF-1α and VEGF in the extracorporeal shock group were higher than the control group (P < .05). The dorsiflexion motion and plantar flexion motion of both groups were increased, and the extracorporeal shock group was higher than the control group (P < .05). Extracorporeal shock wave therapy can regulate subchondral bone homeostasis through TNF-α/HIF-1α/VEGF signaling pathway to treat talus bone marrow edema, reduce the pain degree of talus bone marrow edema, and improve ankle joint function.

Impact of annular nanosecond plasma actuators on drag reduction in transonic flow

During the last few decades, plasma actuators have emerged as promising devices for aerodynamic flow control. This study focuses on the use of nanosecond plasma actuators for such purposes. A thermal phenomenological model is employed to simulate the effects of these actuators. The propagation of shock waves and their interactions for two specific geometries of plasma actuators, linear and annular plasma synthetic jet actuators, are examined here. A comparative analysis of the performance of these two configurations is presented. Furthermore, the geometric characteristics and temperature model are analyzed to provide insights that can be applied to practical problems. The influence of the actuators on a projectile in the transonic flow is also investigated. The results of the present study show that actuators placed in the conical and cylindrical regions of the object do not contribute to drag reduction. Conversely, actuators positioned at the boat-tail and base of the object effectively reduce drag. This drag reduction is primarily attributed to thermal disturbances in the separation area. Additionally, it is observed that the effects of shock waves and their interaction with stationary waves around the projectile are negligible in terms of drag force reduction.

Study on the destructive effects of shock waves on typical cabinets under explosive conditions within the cabin

Study on the destructive effects of shock waves on typical cabinets under explosive conditions within the cabin

Inactivation of MS-2 virus in water by rotational generator of hydraulic shock

This study investigates the effect of hydraulic shock waves on inactivation of MS-2 bacteriophage, a norovirus surrogate. A falling circular jet of water spiked with the MS-2 (∼1000 PFU/mL) was repeatedly impacted by a rotating blade, resulting in occurrence of hydraulic shock waves within the liquid region adjacent to the impact. The proof-of-concept rotational generator of hydraulic shock treating 9 L of water spiked with viruses was able to achieve 3 logs reduction of viral plaque count within 80–100 liquid passes at moderate blade impact velocities (namely, 70 and 88 m/s) despite the water temperature not exceeding 40 °C and no detectible cavitation. Within the first 20 liquid passes, most MS-2 capsid proteins were degraded, with their concentration reduced from 22 μg/mL to only 7.3 μg/mL. Due to the lack of further capsid protein destruction, additional reduction in MS-2 plaque count in subsequent 80 passes is indicative of damage inflicted to the viral recognition receptors. All this suggests that shockwaves of moderate amplitude (few tens of MPa) alone are sufficient for effective viral inactivation. Considering this and the device's good scalability potential, rotational hydraulic shock generators could prove effective in treating virus-contaminated waters.

Mechanism of Spontaneous Acceleration of Slow Flame in Channel

This paper is devoted to the numerical analysis of the spontaneous acceleration of a slow flame in a semi-closed channel. In particular, the flow development in the channel ahead of the propagating flame is analyzed. The applied detailed numerical model allows the clear observation of all features intrinsic to the reacting flow evolution in the channel, including the formation of perturbations on the scale of the boundary layer and their further development. In all considered cases, perturbations of the boundary layer emerge in the early stages of flame acceleration and decay afterward. The flow stabilizes more rapidly in a narrow channel, where the velocity profile is close to the Poiseuille profile. At the same time, the compression waves generated in the reaction zone travel along the channel. The interaction between compression waves in the area of combustion products can lead to the formation of shock waves. The effect of shock waves on the flow in the fresh mixture causes an increase in the flame area and a corresponding flame acceleration. In addition, shock waves trigger boundary-layer instability in wide channels. The perturbations of the boundary layer grow and evolve into vortexes, while further vortex–flame interaction leads to significant flame acceleration.

Comparative analysis of macroscopic traffic models for evaluating shockwaves under lane closures on an urban highway using the LWR model

ABSTRACT Lane closure due to traffic crashes is a complex phenomenon that negatively affects the operational performance of highways and leads to secondary lane closures. The present study investigates the effects of shockwaves caused by a heavy vehicle run-off-road crash on a three-lane urban highway in Isfahan, Iran. Additionally, the study simulates the effects of lane closures on shockwaves and density using the Lighthill, Whitham, and Richards (LWR) theory and macroscopic traffic flow based on field data. An analysis of traffic flow models revealed that one-lane and two-lane closures reduce maximum flow by 29% and 61%, respectively, compared to normal conditions. The results showed that the minimum relative error (RE) for lane closures is associated with shockwave models based on the Underwood speed-density model, expanded using the Taylor series. Therefore, the shockwave model based on the Underwood model with Taylor series expansion outperforms other models.

Effects of acoustic shock waves on the structural and optical properties of cadmium borate

Cadmium borate (CdB₂O₄), an inorganic compound combining transition metals and non-metals, has a broad range of optical applications. In this study, CdB₂O₄ was subjected to acoustic transient pressure using a semi-automatic Reddy tube, with shock pulses applied at counts of 100, 200, 300, and 400 at a Mach number of 1.5, corresponding to a transient pressure of 0.59 MPa and a temperature of 520 K. Control and shock-treated samples were analyzed using XRD, Raman, FTIR, SEM, UV-DRS, and photoluminescence spectroscopy to investigate shock wave effects. The XRD analysis revealed peak disappearance, the formation of new peaks, increased crystallinity, and instability in crystallite size. Raman spectroscopy showed peak disappearance, shifts, and broadening of lattice modes. SEM indicated increased particle size and agglomeration under shock conditions, consistent with changes in crystallinity. UV-DRS analysis shows a slight change in their band gap. Photoluminescence exhibited fluctuating trends in luminescent properties after the shock treatment. The findings reveal that CdB₂O₄'s structural and optical properties are sensitive to acoustic pressure, suggesting its potential for tailored optical behavior in specific applications. These results enhance our understanding of how acoustic pressure affects CdB₂O₄ and open new possibilities for optimizing its use in high-pressure applications.

On the focusing effect and interfacial evolution of incident shock waves impinging on double-layer nested heavy gas bubbles

A detailed numerical study about the planar incident shock wave impinging on heavy bubbles with different components and nested structures was conducted. Results show that the shock wave convergence occurs when the incident shock wave impinging on the pure SF6 bubble or CO2-SF6 nested bubbles, which triggers the shock wave focusing and obtains a high transient pressure. Changing the nested position and radius of the SF6 bubble in CO2-SF6 nested bubbles will change the interactional time and relative position of waves to affect the shock wave focusing time and peak pressure. Specifically, the shock wave focusing effect is enhanced, and the peak pressure is increased when the inner bubble is drifted downstream, high density, and larger sized. Thus, the later the shock wave focusing occurs, the higher the transient maximum pressure. The shock wave focusing process of double-layer nested bubbles is presented as follows: the new small shock wave (SS) formed by the intersection between the incident transmitted shock wave and the transmitted shock wave and another new shock wave formed by the collision of diffracted transmitted shock waves move in opposite directions to squeeze the undisturbed region and finally produce a high instantaneous pressure, where SS plays a major role in shock wave focusing. Further, the greater the intensity and velocity of focusing shock waves, the stronger the focusing effect and the higher the transient pressure.

The dose effectiveness of extracorporeal shockwave on plantar flexor spasticity of ankle in stroke patients: a randomized controlled trial

BackgroundExtracorporeal shockwave therapy (ESWT) has been proven beneficial for post-stroke spasticity (PSS) of ankle plantar flexor muscles. This study aims to investigate the dose-response effectiveness of focused-ESWT and the duration of its effect on the treatment of ankle PSS in stroke patients.MethodsIn this double-blinded randomized controlled trial, stroke patients diagnosed with PSS in the ankle plantar flexor muscles were randomly assigned to two groups. The experimental group received double-dose ESWT (4000 pulses per session) targeting spastic calf muscles, while the control group received half the dose (2000 pulses per session). Both groups underwent four sessions over two weeks. The outcomes, including modified Ashworth Scale (MAS), modified Tardieu Scale (MTS), passive range of motion (PROM) of the ankle, Timed Up and Go (TUG) Test, Barthel index and strain elastography were evaluated at baseline, 1st, 4th, 12th, and 24th week after ESWT.ResultsWithin-group analysis revealed significant improvements in MAS, PROM, TUG Test, and Barthel index for the double-dose ESWT group and improvements in Barthel index for the control group. Between-group analysis revealed greater improvements in TUG Test, Barthel Index and strain elastography for the double-dose ESWT group. Generalized estimating equations analysis indicated that the double-dose ESWT group achieved superior outcomes in the TUG Test, Barthel Index, and strain elastography across various time points and groups.ConclusionsDouble-dose ESWT showed better functional improvement and elastography compared to the control group. ESWT demonstrated dose-response effectiveness for PSS of ankle-equinus.Trial registrationNCT05878223.

Numerical study on cavitation generation induced by the high-speed jet impact on the water surface

The complex interaction between shock waves and two-phase interfaces can generate cavitation. In this study, the cavitation induced by the high-speed jet impact on the water surface was investigated. The mixture fluid is modeled using the barotropic equation of state under the framework of the two-phase flow model, which can describe the mixture of air, water, and vapor with any proportion. Through constructing a 1D Riemann problem for the impact-induced cavitation phase transition, it indicates that the coupling effect of multiple rarefaction waves emitted from the two-phase interface is responsible for the cavitation phase transition inside the liquid. Then, a 3D (three-dimensional) simulation regarding the impact of a high-speed jet on the water surface was conducted and validated against previous experiments that captured the cavitation phase transition phenomenon in the central region after the jet impact. The 3D simulation results revealed the spatial structure and development process of shock waves in detail. The coupling effects of shock waves and two-phase interfaces generate a ring-shaped rarefaction wave, which develops radially inward and superimposes, resulting in the formation of acorn-shaped cavitation bubble nuclei inside the water. The 3D simulation can provide spatial shock/rarefaction wave structures and internal flow details that have never been obtained in experiments, such as shock generation and propagation, rarefaction wave generation and center convergence, and the internal structure of acorn-shaped cavitation nucleation. Furthermore, the influence of the jet velocity on the cavitation intensity was analyzed, and a quantitative relationship was provided.

Difference in rock-breaking characteristics between water-coupling blasting and air-coupling blasting

The water-coupling blasting (WCB) technology has received widespread attention due to its advantages of high efficiency and environmental protection. However, the parameters of WCB in practical engineering are generally determined based on the experience and standards of air-coupling blasting (ACB), leading to poor blasting effects and wastage of explosive energy. The study focuses on comparing the rock-breaking effects of shock waves and explosive gases between WCB and ACB to offer insights for optimizing the design of WCB. Firstly, the stress field in blasting with different coupling mediums was calculated. Then, the shock failure characteristics of rocks between WCB and ACB were analyzed. The results show that the radius of shock failure zones decreases with the increasing decoupling coefficient in WCB and ACB. On this basis, a model for calculating the shock failure range in WCB and ACB was proposed. This model can be utilized to estimate the percentage of fine-grained stone in the two types of blasting. Further, a method for distinguishing between the rock-breaking effects of shock waves and explosive gases was proposed based on the numerical simulation results of blasting damage. A comparative analysis between WCB and ACB on the rock-breaking volume by shock waves and gases was conducted. The results indicate that the failure volumes of rocks induced by shock waves and gases in WCB are 1.4–2.1 times greater than those in ACB, with a decoupling coefficient ranging from 1.26 to 1.71. Finally, a method for determining the charging structure in WCB was discussed, which has been preliminarily validated by field tests. The findings can help regulate rock-breaking effects in blasting by rationally selecting coupling mediums and charging constructions.

Effect of extracorporeal shockwave on gait parameters in patients with plantar fascitis: a randomized controlled trial

BackgroundPlantar fasciitis (PF) is the most common cause of heel pain affecting both young active patients and older sedentary individuals. It most often arises as a result of degenerative changes in the proximal plantar fascia.AimThe purpose of this study was to investigate the effect of extracorporeal shockwave on gait parameters in patients with plantar fasciitis.DesignA randomized controlled clinical trial.SettingThe outpatient physiotherapy clinic of the teaching hospital Shibin El Kom.MethodsParticipants were randomly divided into two equal groups. Group (A) (study group): received extracorporeal shockwave therapy one session per week and traditional treatment (ultrasound, stretching exercises, and strengthening exercises) three sessions per week for 4 weeks. Group (B)(the control group): received traditional treatment (ultrasound, stretching exercises, and strengthening exercises) 3 sessions per week for 4 weeks. The pre- and post-treatment development of the patients was evaluated by visual analog scale (VAS) to measure pain, foot function index (FFI) to measure foot function, and Kinovea software to analyze gait parameters (stride length, stride time, walking speed, and cadence).ResultsBoth groups showed improvement in all study variables, but the study group showed more improvement. There was a statistically significant decrease in VAS (p = 0.001), a significant decrease in FFI (p = 0.001), a significant increase in stride length (p = 0.001), a significant decrease in stride time (p = 0.001), a significant increase in walking speed (p = 0.001), and a significant increase in cadence (p = 0.01) post-treatment compared to group (B).ConclusionExtracorporeal shockwave treatment is regarded as a useful treatment for improving gait parameters in patients with plantar fasciitis.Clinical rehabilitation impactExtracorporeal shockwave therapy improved gait parameters in patients with plantar fasciitis as it increases stride length, walking speed, cadence, and decreases stride time. So, it is recommended to be included in the rehabilitation program for patients with plantar fasciitis and gait disabilities.

Enhancing NiCrBSi coating by the spatial selectivity of in-situ shock wave assisted laser cladding

The composite energy field laser cladding (LC) can improve the mechanical properties of coatings. Based on the spatial selectivity of laser shock, in-situ shock wave assisted LC (in-situ SWALC) was proposed to fabricate NiCrBSi coatings. Firstly, based on the self-developed in-situ SWALC system, four NiCrBSi coatings were prepared on the 16Mn substrate by changing the centre-to-centre distance (CTCD) of two laser spots. Then, the differences of microstructure and element content between LC coating and in-situ SWALC coatings were analyzed. Vickers hardness tester and wear tester were used to compare the influence of CTCD. Finally, based on the theoretical calculation and propagation characteristics of the shock wave, combined with real-time monitoring of the molten pool during the in-situ SWALC process using high-speed imaging, the strengthening mechanism of the in-situ SWALC coatings was revealed. When the CTCD was 0.9 mm, the NiCrBSi coating had the highest hardness and wear properties, which was attributed to the effects of shock wave on the molten pool flow and solidification process. Therefore, the spatial selectivity of in-situ SWALC will play a important role in improving coating performance and energy efficiency, which contributes to the UN Sustainable Development Goal 9 (UN SDG 9).

Effect of extracorporeal shock wave combined with autologous platelet-rich plasma injection on rotator cuff calcific tendinitis: study protocol for a randomized controlled trial

BackgroundRotator cuff calcific tendinitis (RCCT) is a common shoulder disease whose main symptoms include shoulder pain, limited mobility, and calcification deposits in the shoulder. Traditional treatment methods have certain limitations, so finding new treatment methods has become the focus of research. Extracorporeal shock wave (ESW) and platelet-rich plasma (PRP) treatments have attracted much attention due to their non-invasive and tissue repair-promoting properties; however, the efficacy of their combined treatment in RCCT remains unclear.MethodsThis study is designed as a single-center, assessment-blind, randomized controlled clinical trial with three parallel groups. Sixty subjects will be recruited and randomly divided into the ESW group, PRP group, and ESW combined with PRP group, in a 1:1:1 ratio. The entire intervention period is 4 weeks, and the follow-up period is 4 weeks. Outcomes will be measured at baseline (T0), after 1 week of intervention (T1), after 2 weeks of intervention (T2), after 4 weeks of intervention (T3), and after an additional 4 weeks of follow-up period (T4). The primary endpoint is the VAS score. Secondary endpoints are ASES, CMS, UCLA, and the location and size of calcified areas.DiscussionThis study aims to evaluate the efficacy of ESW therapy combined with PRP in treating RCCT. We compare the effects of single and combined treatments to explore their impact on disease symptoms, functional improvement, and calcification regression. This provides a scientific basis for identifying more effective treatment options.Trial registrationClinicalTrials.gov NCT06372600. Registered on April 17, 2024; version 1.

Precision micro-particle removal from through-holes via laser-induced plasma shockwaves in additive manufacturing

This study introduces a novel Laser-Induced Plasma (LIP) technique for the non-contact, rapid removal of nano and microparticles from through-holes in Additive Manufacturing (AM) components. This method is crucial for high-value applications, such as medical devices, compact heat exchangers, and aerospace engineering, which require efficient cleaning of intricate parts with holes and channels to address high failure costs. The technique leverages shockwaves generated by LIP to target and clean these complex geometries. The research focuses on two main areas: (i) characterizing the effects of shockwaves in semi-cylindrical channels to understand interactions with complex geometries, and (ii) quantitatively analyzing the removal of Fe-271 microparticles from semi-cylindrical channels of silicon (Si) wafers, selected for their consistent surface properties compared to the rough textures of AM-produced surfaces. Utilizing the experimental set-up Laser-Induced Plasma LIP Cleaning for Additive Manufacturing (LIPCAM), the study demonstrates that complete microparticle removal is achievable up to 20 mm from the plasma source with variable laser pulses. The results indicate that particles larger than 27 μm are entirely removed after a single pulse, and particles larger than 21 μm are removed after 50 pulses. These findings highlight the method's effectiveness in achieving high particle removal efficiency across different distances and particle sizes, thus ensuring thorough decontamination of complex internal structures. The study underscores the potential of this method to enhance the reliability and safety of critical AM builds, making it a viable solution for industries where precision and cleanliness are paramount.

Extracorporeal Shock Wave and Melatonin Alleviate Joint Capsule Fibrosis after Knee Trauma in Rats by Regulating Autophagy.

Joint contracture is a common clinical problem affecting joint function. Capsule fibrosis plays a pivotal role in the progression of Joint contracture. Previous studies have reported that autophagy plays a regulatory role in visceral fibrosis. This study aimed to investigate whether extracorporeal shock wave therapy (ESWT) and melatonin alleviate joint capsule fibrosis in rats with extended knee joint contracture by regulating autophagy. A rat knee joint extension contracture model was made. Then, the rats were treated with ESWT, melatonin, ESWT + melatonin, or ESWT + melatonin + mTOR agonist for 4 weeks. The range of motion (ROM) of the knee joints was measured. Joint capsules were collected and observed for pathological changes by H&E and Masson staining. LC3B protein expression was evaluated by immunofluorescence staining. TGF-β1, MMP-1, Col-Ⅰ, Col-Ⅲ, LC3, ATG7, Beclin1, p-AMPK, p-mTOR and p-ULK1 protein expressions were measured by Western blot assay. The intervention groups had significantly improved ROM of knee joint (P < 0.05), significantly improved pathological changes on HE and Masson staining, significantly decreased protein expressions of TGF-β1, MMP-1, Col-Ⅰ, Col-Ⅲ and pmTOR (P < 0.05), and significantly increased protein expressions of LC3B, LC3II/LC3I ratio, ATG7, Beclin1, p-AMPK, and p-ULK1 (P < 0.05). Among these groups, the effects demonstrated by the ESWT + melatonin group were the best. With the mTOR agonist supplement, the therapeutic effects of extracorporeal shock waves and melatonin were significantly reduced. ESWT plus melatonin alleviated knee joint capsule fibrosis in rats by regulating autophagy.

High efficiency femtosecond laser ablation of alumina ceramics under the filament induced plasma shock wave

Femtosecond laser filament enables energy transfer over long distances, which is of great value for studying long-range ablation. However, the energy coupling of filament with the plasma generated by the ablation process leads to a very complex behavior which limits the ablation efficiency. This study systematically investigated the ablation mechanism of laser-induced filament in alumina ceramic. The plasma shock wave was initially investigated using spectral detection techniques combined with Sedov-Taylor theory. The results indicated that the maximum plasma shock wave reached 30 MPa under the irradiated by a 1 mJ fs laser. The theoretical analysis confirmed the effectiveness of the filament-induced plasma shock wave in enhancing the ablation rate of alumina ceramic. In this context, the experimental studies were conducted with varying filament positions and pulse energies, and the corresponding ablation rates for each parameter were investigated. The filament in the ablation process was found to has a secondary sputtering effect, which is an effective contributor to enhance the ablation rate. The corresponding ablation depth reach to 550 μm while achieving an ablation rate of 3.1 μm3/μJ. Finally, the coupling mechanism between the femtosecond laser filament and the plasma shock wave was systematically revealed. This research will facilitate future laser remote ablation applications with high efficiency.

Comparative analysis of blast prediction software for far-field shock wave effects behind a blast wall

This paper investigates a selection of current and emerging software used in the prediction of overpressure generated through the detonation of a high explosive in the far field behind a blast wall. In particular, this paper compares the software Autodyn, blastFoam, ProSAir, Viper::Blast and WALAIR++. These packages are compared by simulating a 100 kg TNT explosive charge at a stand-off distance of 25 m from a complex structure, then reviewing the performance in terms of the overpressure results, speed of each modelling package, the degree of effect from mesh, and domain sizes and ease of use. A live experimental trial representing the simulation was also performed, although it used a similar but different explosive, for a high-level comparison. The live-trial instrumentation design details are reviewed and compared with best practice. The choice of software is found to lead to variations in peak pressure predictions of 28%, specific impulse by 10% and the simulation speed can vary by a factor of up to 1600 for this type of study. This shows that the choice of blast software package can have a significant impact on the accuracy and attainability of blast predictions.