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Structural uncertainty quantification of Reynolds-Averaged Navier–Stokes closures for various shock-wave/boundary layer interaction flows
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作者 Fanzhi ZENG Tianxin ZHANG +2 位作者 Denggao TANG Jinping LI Chao YAN 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第3期34-48,共15页
Accurate prediction of Shock-Wave/Boundary Layer Interaction(SWBLI)flows has been a persistent challenge for linear eddy viscosity models.A major limitation lies in the isotropic representation of the Reynolds stress,... Accurate prediction of Shock-Wave/Boundary Layer Interaction(SWBLI)flows has been a persistent challenge for linear eddy viscosity models.A major limitation lies in the isotropic representation of the Reynolds stress,as assumed under the Boussinesq approximation.Recent studies have shown promise in improving the prediction capability for incompressible separation flows by perturbing the Reynolds-stress anisotropy tensor.However,it remains uncertain whether this approach is effective for SWBLI flows,which involve compressibility and discontinuity.To address this issue,this study systematically quantifies the structural uncertainty of the anisotropy for oblique SWBLI flows.The eigenspace perturbation method is applied to perturb the anisotropy tensor predicted by the Menter Shear–Stress Transport(SST)model and reveal the impacts of anisotropy on the prediction of quantities of interest,such as separation and reattachment positions,wall static pressure,skin friction,and heat flux.The results demonstrate the potential and reveal the challenges of eigenspace perturbation in improving the SST model.Furthermore,a detailed analysis of turbulent characteristics is performed to identify the source of uncertainty.The findings indicate that eigenspace perturbation primarily affects turbulent shear stress,while the prediction error of the SST model is more related to turbulent kinetic energy. 展开更多
关键词 shock-wave/boundary layer interaction(SWBLI) Turbulence models Uncertainty analysis Eigenspace perturbation Anisotropy
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Combination of low-energy shock-wave therapy and bone marrow mesenchymal stem cell transplantation to improve the erectile function of diabetic rats 被引量:16
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作者 Hai-Tao Shan Hai-Bo Zhang +6 位作者 Wen-Tao Chen Feng-Zhi Chen Tao Wang Jin-Tai Luo Min Yue Ji-Hong Lin An-Yang Wei 《Asian Journal of Andrology》 SCIE CAS CSCD 2017年第1期26-33,共8页
Stem cell transplantation and low-energy shock-wave therapy (LESWT) have emerged as potential and effective treatment protocols for diabetic erectile dysfunction. During the tracking of transplanted stem cells in di... Stem cell transplantation and low-energy shock-wave therapy (LESWT) have emerged as potential and effective treatment protocols for diabetic erectile dysfunction. During the tracking of transplanted stem cells in diabetic erectile dysfunction models, the number of visible stem cells was rather low and decreased quickly. LESWT could recruit endogenous stem cells to the cavernous body and improve the microenvironment in diabetic cavernous tissue. Thus, we deduced that LESWT might benefit transplanted stem cell survival and improve the effects of stem cell transplantation. In this research, 42 streptozotocin-induced diabetic rats were randomized into four groups: the diabetic group (n = 6), the LESWT group (n = 6), the bone marrow-derived mesenchymal stem cell (BMSC) transplantation group (n = 15), and the combination of LESWT and BMSC transplantation group (n = 15). One and three days after BMSC transplantation, three rats were randomly chosen to observe the survival numbers of BMSCs in the cavernous body. Four weeks after BMSC transplantation, the following parameters were assessed: the surviving number of transplanted BMSCs in the cavernous tissue, erectile function, real-time polymerase chain reaction, and penile immunohistochemical assessment. Our research found that LESWT favored the survival of transplanted BMSCs in the cavernous body, which might be related to increased stromal cell-derived factor-1 expression and the enhancement of angiogenesis in the diabetic cavernous tissue. The combination of LESWT and BMSC transplantation could improve the erectile function of diabetic erectile function rats more effectively than LESWT or BMSC transplantation performed alone. 展开更多
关键词 bone marrow mesenchymal stem cell diabetes mellitus erectile function low-energy shock-wave therapy
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A study on turbulence transportation and modification of Spalart–Allmaras model for shock-wave/turbulent boundary layer interaction flow 被引量:9
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作者 Ma Li Lu Lipeng +1 位作者 Fang Jian Wang Qiuhui 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2014年第2期200-209,共10页
It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development ... It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development of turbulent kinetic energy in impinging shock-wave/turbulent bound- ary layer interaction flow at Mach 2.25 is analyzed based on the data of direct numerical simulation (DNS). It is found that the turbulent kinetic energy is amplified by strong shear in the separation zone and the adverse pressure gradient near the separation point. The pressure gradient was non-dimensionalised with local density, velocity, and viscosity. Spalart Allmaras (S A) model is modified by introducing the non-dimensional pressure gradient into the production term of the eddy viscosity transportation equation. Simulation results show that the production and dissipation of eddy viscosity are strongly enhanced by the modification of S-A model. Compared with DNS and experimental data, the wall pressure and the wall skin friction coefficient as well as the velocity profile of the modified S-A model are obviously improved. Thus it can be concluded that the mod- ification of S-A model with the pressure gradient can improve the predictive accuracy for simulat- ing the shock-wave/turbulent boundary laver interaction. 展开更多
关键词 Eddy viscosity Pressure gradient shock-wave/turbulentboundary layer interaction Spalart-Allmaras model Turbulent kinetic energytransport property
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Large-eddy simulation of shock-wave/turbulent boundary layer interaction with and without Spark Jet control 被引量:11
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作者 Yang Guang Yao Yufeng +3 位作者 Fang Jian Gan Tian Li Qiushi Lu Lipeng 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第3期617-629,共13页
The efficiency and mechanism of an active control device "'Spark Jet" and its application in shock-induced separation control are studied using large-eddy simulation in this paper. The base flow is the interaction ... The efficiency and mechanism of an active control device "'Spark Jet" and its application in shock-induced separation control are studied using large-eddy simulation in this paper. The base flow is the interaction of an oblique shock-wave generated by 8° wedge and a spatially-developing Ma = 2.3 turbulent boundary layer. The Reynolds number based on the incoming flow property and the boundary layer displacement thickness at the impinging point without shock-wave is 20000. The detailed numerical approaches were presented. The inflow turbulence was generated using the digital filter method to avoid artificial temporal or streamwise periodicity. The , merical results including velocity profile, Reynolds stress profile, skin friction, and wall pressure were sys- tematically validated against the available wind tunnel particle image velocimetry (PIV) measure- ments of the same flow condition. Further study on the control of flow separation due to the strong shock-viscous interaction using an active control actuator "'Spark Jet'" was conducted. The single-pulsed characteristic of the device was obtained and compared with the experiment. Both instantaneous and time-averaged flow fields have shown that the jet flow issuing from the actuator cavity enhances the flow mixing inside the boundary layer, making the boundary layer more resis- tant to flow separation. Skin friction coefficient distribution shows that the separation bubble length is reduced by about 35% with control exerted. 展开更多
关键词 Large-eddy simulation shock-wave:Turbulent boundary layer INTERACTION Spark Jet control
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Shock-wave impact on the knee joint affected with osteoarthritis and after arthroplasty 被引量:1
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作者 Galina Eremina Alexey Smolin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第2期1-10,共10页
Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of... Degenerative diseases significantly reduce the quality of human life.Non-invasive treatments are used in the initial stages of osteoarthritis(OA).Total knee arthroplasty is used in the late stages of osteoarthritis of the knee joint.Non-invasive methods based on mechanical action are also used for the rehabilitation of a patient after arthroplasty.This paper presents numerical models of the knee joint with degenerative OA changes and arthroplasty.Using these models,a computational study was made of the influence of the intensity of shock-wave exposure on the conditioning for the regeneration of bone and cartilage tissues.Based on the modeling results,it was found that in the knee joint with degenerative OA changes,conditions for the regeneration of cartilage and meniscus tissues were fulfilled under medium and highintensity loading.Under high-intensity loading(up to 0.9 m J/mm^(2)),the stress level was significantly below the ultimate value required for fracture.At knee arthroplasty,the conditions for bone tissue regeneration around the tibia component are fulfilled only under high-intensity loading. 展开更多
关键词 Knee joint Total knee replacement shock-wave therapy Computer simulation Method of movable cellular automata
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Distribution Regularity of Muzzle Shock-Wave Inside Protective Cover 被引量:1
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作者 WU Jun LIU Jingbo DU Yixin 《Transactions of Tianjin University》 EI CAS 2006年第B09期161-164,共4页
The injury of gunners caused by muzzle shock-wave has always been a great problem when firing inside the protective cover. The distribution regularity and personnel injury from the muzzle blast-wave were investigated ... The injury of gunners caused by muzzle shock-wave has always been a great problem when firing inside the protective cover. The distribution regularity and personnel injury from the muzzle blast-wave were investigated by both test and numerical simulation. Through the inside firing test, the changes of overpressure and noise have been measured at different measuring points in the thin-wall cover structure with different open widths and shallow covering thickness. The distribution regularity of muzzle shock-wave with different firing port widths is calculated by ANSYS/LSDYNA software. The overpressure distribution curves of muzzle shock-wave inside the structure can be obtained by comparing the test results with the numerical results. Then, the influence of open width and shallow covering thickness is proposed to give a reference to the protective design under the condition of the inside firing with the same cannon caliber. 展开更多
关键词 artillery inside firing muzzle shock-wave OVERPRESSURE distribution regularity
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Quantum Electrostatic Shock-Waves in Symmetric Pair-Plasmas
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作者 Massoud Akbari-Moghanjoughi 《Open Journal of Acoustics》 2012年第2期72-79,共8页
In this paper, the quantum hydrodynamics (QHD) model is used to study the propagation of small- but finite-amplitude quantum electrostatic shock-wave in an inertial-less symmetric pair (ion) plasma with immobile backg... In this paper, the quantum hydrodynamics (QHD) model is used to study the propagation of small- but finite-amplitude quantum electrostatic shock-wave in an inertial-less symmetric pair (ion) plasma with immobile background positive constituents. The dispersion due to the quantum tunneling and inertial effects as well as dissipation caused by particle collisions leading to the shock-like or double-layer structures are considered. Investigation of both the stationary and traveling-wave solutions to Kortewege-de Veries-Burgers evolution equation show that critical values exist which govern the type of collective plasma structures. Current analysis apply to diverse kind of symmetric plasmas such as laboratory inertially confined or astrophysical pair-ion or electron-positron degenerate plasmas. 展开更多
关键词 ELECTROSTATIC shock-wave QUANTUM Plasma FERMI Statistics QUANTUM Hydrodynamics KdVB Equation QHD
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Near-wall behaviors of oblique-shock-wave/turbulent-boundary-layer interactions
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作者 Mingsheng YE Ming DONG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第10期1357-1376,共20页
A direct numerical simulation (DNS) on an oblique shock wave with an incident angle of 33.2° impinging on a Mach 2.25 supersonic turbulent boundary layer is performed. The numerical results are confirmed to be ... A direct numerical simulation (DNS) on an oblique shock wave with an incident angle of 33.2° impinging on a Mach 2.25 supersonic turbulent boundary layer is performed. The numerical results are confirmed to be of high accuracy by comparison with the reference data. Particular efforts have been made on the investigation of the near-wall behaviors in the interaction region, where the pressure gradient is so significant that a certain separation zone emerges. It is found that, the traditional linear and loga- rithmic laws, which describe the mean-velocity profiles in the viscous and meso sublayers, respectively, cease to be valid in the neighborhood of the interaction region, and two new laws of the wall are proposed by elevating the pressure gradient to the leading order. The new laws are inspired by the analysis on the incompressible separation flows, while the compressibility is additionally taken into account. It is verified by the DNS results that the new laws are adequate to reproduce the mean-velocity profiles both inside and outside the interaction region. Moreover, the normalization adopted in the new laws is able to regularize the Reynolds stress into an almost universal distribution even with a salient adverse pressure gradient (APG). 展开更多
关键词 shock wave turbulent boundary layer direct numerical simulation (DNS) adverse pressure gradient (APG) separation
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Can extracorporeal shock-wave therapy be used for the management of lateral elbow tendinopathy?
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作者 Dimitrios Stasinopoulos 《World Journal of Methodology》 2018年第3期37-39,共3页
Lateral elbow tendinopathy(LET) is one of the two most common tendinopathies of the upper limb. The most effective treatment in the management of LET is the exercise program. Clinicians combine exercise program with o... Lateral elbow tendinopathy(LET) is one of the two most common tendinopathies of the upper limb. The most effective treatment in the management of LET is the exercise program. Clinicians combine exercise program with other physiotherapy, electrotherapeutic and no, techniques. Extracorporeal shock wave therapy(ESWT) is one of the most common recommended electrotherapeutic modalities for the management of LET. Further research is needed to find out the optimal treatment protocol of ESWT in the management of 展开更多
关键词 LATERAL ELBOW TENDINOPATHY EXTRACORPOREAL shock wave THERAPY Exercise program Electrotherapy Tennis ELBOW LATERAL EPICONDYLITIS Physiotherapy Calcific TENDINOPATHY
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Structure Transformations in the Polycrystalline (Ti,Nb)<sub>3</sub>Al Alloy under Shock-Wave Loading
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作者 Nataliya V. Kazantseva Evgenii V. Shorokhov 《Journal of Modern Physics》 2011年第10期1141-1145,共5页
Structure transformations in the two-phase (Ti, Nb)3Al alloy, induced by shock-wave loading, were studied. The samples were subjected to an impact of a steel plate. The maximum pressure on the samples’ surfaces was 1... Structure transformations in the two-phase (Ti, Nb)3Al alloy, induced by shock-wave loading, were studied. The samples were subjected to an impact of a steel plate. The maximum pressure on the samples’ surfaces was 100 GPa, while the maximum temperature was 573 K. The β0→α2 phase transformation occurred during strong deformations. High temperature rectilinear dislocations (such types of dislocations usually could arise at 1073 K) with the c-component, which occasionally formed slip bands, were located at the α2-phase grains after the shock. The deformation α2-phase twins were not observed. 展开更多
关键词 TI3AL Phase Transformation Shock Waves
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Experimental and Numerical Investigations of Shock-Wave Boundary Layer Interactions in a Highly Loaded Transonic Compressor Cascade 被引量:1
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作者 MENG Fanjie LI Kunhang +2 位作者 GUO Penghua GAN Jiuliang LI Jingyin 《Journal of Thermal Science》 SCIE EI CSCD 2024年第1期158-171,共14页
Experimental and numerical investigations were conducted to investigate the variations of shock-wave boundary layer interaction(SBLI) phenomena in a highly loaded transonic compressor cascade with Mach numbers.The sch... Experimental and numerical investigations were conducted to investigate the variations of shock-wave boundary layer interaction(SBLI) phenomena in a highly loaded transonic compressor cascade with Mach numbers.The schlieren technique was used to observe the shock structure in the cascade and the pressure tap method to measure the pressure distribution on the blade surface.The unsteady pressure distribution on blade surface was measured with the fast-response pressure-sensitive paint(PSP) technique to obtain the unsteady pressure distribution on the whole blade surface and to capture the shock oscillation characteristics caused by SBLI.In addition,the Reynolds Averaged Navier Stokes simulations were used to compute the three-dimensional steady flow field in the transonic cascade.It was found that the shock wave patterns and behaviors are affected evidently with the increase in incoming Mach number at the design flow angle,especially with the presence of the separation bubble caused by SBLI.The time-averaged pressure distribution on the blade surface measured by PSP technique showed a symmetric pressure filed at Mach numbers of 0.85,while the pressure field on the blade surface was an asymmetric one at Mach numbers of 0.90 and 0.95.The oscillation of the shock wave was closely with the flow separation bubble on the blade surface and could transverse over nearly one interval of the pressure taps.The oscillation of the shock wave may smear the pressure jump phenomenon measured by the pressure taps. 展开更多
关键词 transonic flow transonic compressor cascade shock-wave boundary-layer interaction shock oscillation
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Treatment of urinary lithiasis following kidney transplantation with extracorporeal shock-wave lithotripsy 被引量:6
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作者 LI Sha-dan WANG Qing-tang CHEN Wei-guo 《Chinese Medical Journal》 SCIE CAS CSCD 2011年第9期1431-1434,共4页
Background The incidence of urinary lithiasis following kidney transplantation is very low, and decision-supporting data are not available. The aim of this study was to review the diagnosis and treatment of urinary li... Background The incidence of urinary lithiasis following kidney transplantation is very low, and decision-supporting data are not available. The aim of this study was to review the diagnosis and treatment of urinary lithiasis following kidney transplantation, which is of realistic significance to reduce urinary lithiasis following kidney transplantation, prolong the survival of renal allografts.Methods The incidence, diagnosis and treatment of urinary lithiasis in ten patients following kidney transplantation were analyzed retrospectively. Seven out of these patients had stones sized approximately 0.4-1.1 cm, and they were treated with low-voltage, low-frequency extracorporeal shock-wave lithotripsy (ESWL). Two patients had stones sized <0.3 cm and they underwent cystoscopy and ureteroscopy. The ureteral catheter endoscopes were inserted in a retrograde manner to mobilize stones repeatedly. After elimination of obstruction, a ureteral double J stent was indwelt.One patient had a pelvic stone (1.2 cm), which was removed surgically.Results The major clinical manifestations were hematuria, oliguria or anuria. Some patients were asymptomatic and they were diagnosed through laboratory tests and imaging examinations, e.g., ultrasonography. After elimination of obstruction, subjective symptoms disappeared in all patients, and the function of renal allografts recovered. A six-month follow-up indicated no remnant stones or lithiasis relapse.Conclusions The diagnosis and treatment of renal allograft lithiasis are challenging. After prompt and appropriate treatment, the prognosis was satisfactory, and permanent renal functional impairment did not occur in most patients. 展开更多
关键词 kidney transplantation LITHIASIS extracorporeal shock-wave lithotripsy
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液相冲击波破岩等离子体通道生长发展机理及敏感性探索 被引量:1
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作者 祝效华 唐无忌 +1 位作者 刘伟吉 罗云旭 《天然气工业》 北大核心 2025年第1期14-24,共11页
地球深层、超深层油气资源丰富,但深部地层具有岩性致密、硬度高、研磨性强等特点,采用传统旋转钻井方式成本高、效率低,亟需探索针对深层、超深层硬地层的新型破岩技术。液相放电冲击波破岩技术因其高效、绿色、能量可控等特点受到广... 地球深层、超深层油气资源丰富,但深部地层具有岩性致密、硬度高、研磨性强等特点,采用传统旋转钻井方式成本高、效率低,亟需探索针对深层、超深层硬地层的新型破岩技术。液相放电冲击波破岩技术因其高效、绿色、能量可控等特点受到广泛关注,为研究液相放电等离子体通道生长发展机理与液相放电等离子体通道的参数敏感性,基于电流场、传热场以及带电粒子碰撞扩散方程建立了二维液相的“针—针对排型”放电模型,分析了不同放电参数(加载电压、电极尖端形状、电极间距、电极夹角等)下等离子体通道内能量密度及局部电场强度等参数变化规律。研究结果表明:(1)加载电压、电极尖端形状以及电极间距是等离子体通道内能量密度大小的主要影响因素,其最佳放电电压为140~180 kV;(2)椭圆形放电电极形成的等离子体放电通道具有“区域宽、数值高”等特征,具备高电能密度的同时,减小了对电极头的损伤,可作为优选电极类型;(3)电极间距应在满足最小击穿场强的前提下,尽可能增大电极间距;(4)电极夹角对液相放电过程产生的直接影响微乎其微,但电极夹角的改变会影响等离子体通道在水中的形成位置。结论认为,该研究结果为液电破岩装置的研制和参数优化提供了重要参考,为未来液相冲击波技术在油气工程领域的探索与应用提供了理论支撑。 展开更多
关键词 液相放电 等离子体通道 液相冲击波 能量密度 局部电场 电击穿 参数敏感性分析
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基于燃气爆炸试验优化TNT当量法预测冲击波超压研究 被引量:1
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作者 程建华 翁应康 +1 位作者 顿志元 张紫君 《消防科学与技术》 北大核心 2025年第2期223-229,共7页
为探究不同定点距离下甲烷-空气预混气体爆炸冲击波超压预测方法的适用性和准确性,采用自制燃气管道爆炸装置进行了不同浓度下冲击波超压随距离变化特性试验研究,选用TNT当量法与TNO多能法分析了不同定点距离下不同浓度甲烷-空气预混气... 为探究不同定点距离下甲烷-空气预混气体爆炸冲击波超压预测方法的适用性和准确性,采用自制燃气管道爆炸装置进行了不同浓度下冲击波超压随距离变化特性试验研究,选用TNT当量法与TNO多能法分析了不同定点距离下不同浓度甲烷-空气预混气体爆炸冲击波超压的差异性,并基于TNT当量法对不同定点距离下燃气爆炸冲击波超压公式进行了修正。结果表明:甲烷-空气预混气体爆炸冲击波的衰减与冲击波超压成正比,与定点距离成反比;随着甲烷-空气预混气体浓度增加,冲击波超压曲线由介于TNT当量法与TNO多能法之间,逐渐演变为近端高于TNT当量法、远端低于TNO多能法;当甲烷-空气预混气体体积分数为9.5%、11.5%、13.5%时,修正后的冲击波超压随距离变化结果相较于实测值偏差绝对值百分比均低于25%。 展开更多
关键词 燃气爆炸 爆燃 TNT当量法 冲击波超压 偏差绝对值百分比
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基于频域干涉法测量激光加载亚微米铝膜的冲击参数
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作者 陶天炯 翁继东 +8 位作者 王翔 刘盛刚 马鹤立 李成军 贾兴 陈龙 吴建 唐隆煌 陈永超 《高压物理学报》 北大核心 2025年第4期1-8,共8页
针对镀于石英上的亚微米铝膜样品,将飞秒激光(脉宽35 fs、能量0.5 mJ、中心波长800 nm)聚焦其表面,通过激光烧蚀引起铝的快速热膨胀,驱动冲击波传播,使铝样品获得高压加载。透过铝样品背面的石英窗口,采用频域干涉技术,同时测量了冲击... 针对镀于石英上的亚微米铝膜样品,将飞秒激光(脉宽35 fs、能量0.5 mJ、中心波长800 nm)聚焦其表面,通过激光烧蚀引起铝的快速热膨胀,驱动冲击波传播,使铝样品获得高压加载。透过铝样品背面的石英窗口,采用频域干涉技术,同时测量了冲击径向位移轮廓、粒子速度和冲击波传播速度。通过监测脉冲能量和打靶位置,提高了多发次实验的重复性。采用相位比较算法对实验数据进行分析,实现了亚纳米级的位移分辨率和亚皮秒级的时间分辨率,成功地获得了铝膜在约130 GPa压力下的界面冲击轮廓演化历史。 展开更多
关键词 冲击波 飞秒激光 频域干涉 物态方程
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基于深度学习的矿井瓦斯爆炸源强度和位置反演方法
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作者 尚晓吉 杨忠原 +2 位作者 张志镇 杨维好 翟成 《采矿与安全工程学报》 北大核心 2025年第5期1204-1213,共10页
针对矿井瓦斯爆炸源反演问题,分别构建了一维循环神经网络(RNN)和二维卷积神经网络(CNN)深度学习模型,对不同测点位置及超压数据下的爆炸源强度和位置进行反演研究。通过分析瓦斯爆炸超压随距离的衰减规律,利用一维RNN模型处理时间序列... 针对矿井瓦斯爆炸源反演问题,分别构建了一维循环神经网络(RNN)和二维卷积神经网络(CNN)深度学习模型,对不同测点位置及超压数据下的爆炸源强度和位置进行反演研究。通过分析瓦斯爆炸超压随距离的衰减规律,利用一维RNN模型处理时间序列数据的优势,实现了瓦斯爆炸源强度和位置的反演。将研究扩展到二维空间,进一步设计了可同步处理测点位置与最大超压数据的二维CNN模型,针对已有瓦斯爆炸数据进行了反演。研究结果表明:所构建的深度学习模型在测试工况上表现出显著的反演准确性,测试工况的均方误差值为0.0003,决定系数(R2)值为0.8831,误差显著低于基线模型,且反演结果与真实工况结果高度一致。研究成果为巷道瓦斯爆炸事故预防与控制提供了有效的技术支撑。 展开更多
关键词 爆炸源反演 深度学习 冲击波超压 神经网络模型 瓦斯爆炸
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水下钻孔爆破激发水中冲击波的机制研究
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作者 杨洋 卢文波 +4 位作者 王洋 黄宇峰 王高辉 陈明 严鹏 《振动与冲击》 北大核心 2025年第12期269-278,共10页
水下爆炸激发水中冲击波的超压峰值主要借用库尔公式,并未考虑水下钻孔爆破激发水中冲击波的机制。针对水下钻孔爆破激发水中冲击波的超压缺乏可靠预测方法的问题,首先从理论上对水-炸药-岩体组成的爆破系统分析了破岩及激发水击波过程... 水下爆炸激发水中冲击波的超压峰值主要借用库尔公式,并未考虑水下钻孔爆破激发水中冲击波的机制。针对水下钻孔爆破激发水中冲击波的超压缺乏可靠预测方法的问题,首先从理论上对水-炸药-岩体组成的爆破系统分析了破岩及激发水击波过程。接着通过对爆炸应力波作用下水击波峰值压力的理论解和数值解对比发现,当爆炸应力波刚进入弹性变形区时,数值解偏小,说明岩体中弹塑性变形区是一个由塑性变形区逐渐过渡到弹性变形区,随着距离逐渐增加,进入岩体的弹性变形区,数值解和理论解拟合效果良好。进一步地,基于SPH-FEM耦合方法,模拟了炮孔周围爆轰产物粒子的运动过程,并结合长江航道建设工程现场的单孔水下爆破试验数据,对水击波波形特征进行了比较和验证。研究结果表明:水下钻孔爆破激发水中冲击波的机制共分为三种。炸药在炮孔内起爆后,爆炸应力波遇到岩石和水的交界面时会发生复杂的透反射过程,一部分会从交界面反射回来,另一部分会在交界面上发生透射激发出水中冲击波;随着爆轰波的传播,爆生气体随后从炮孔孔口喷出,在水中激发出水中冲击波;受爆炸冲击波影响,炮孔空腔开始发生径向动力膨胀,随后裂纹进一步拓展,完成岩体的鼓包破碎致使爆生气体膨胀,从岩体鼓包的裂隙向水中逸散,并在水中激发出水中冲击波。 展开更多
关键词 水下钻孔爆破 应力波 爆生气体 水击波 单孔爆破
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一种新型混合气体多松弛动理学模型方程及其验证分析
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作者 彭傲平 吴俊林 李志辉 《应用数学和力学》 北大核心 2025年第10期1245-1255,共11页
为研究跨流域气体混合物输运现象的流动机理,从气体动理学理论的基本方程Boltzmann方程出发,发展了一种适于混合气体的多松弛碰撞模型方程,并建立了与DSMC方法相适应的碰撞松弛频率表达式.模拟了多组元混合气体一维激波结构问题,与DSMC... 为研究跨流域气体混合物输运现象的流动机理,从气体动理学理论的基本方程Boltzmann方程出发,发展了一种适于混合气体的多松弛碰撞模型方程,并建立了与DSMC方法相适应的碰撞松弛频率表达式.模拟了多组元混合气体一维激波结构问题,与DSMC结果的对比表明:发展的模型方程能较好地反映激波内部混合气体整体及各组元的宏观参数变化过程,能用于模拟和分析混合气体各组元的扩散规律,验证了该多松弛模型方程的有效性和正确性.模拟结果表明:分子质量最小的组元扩散效应最显著,但受其他组元的影响较小,且流动的非平衡效应主要由分子质量最大的组元产生;在激波内部因温度梯度引起的热扩散对分子质量大小更加敏感,同时,组元浓度梯度引起的质量扩散使组元分离,在激波下游产生显著的非平衡效应,且在多组元混合气体中,中等质量分子的加入增大了大质量分子的扩散,加大了分离效应. 展开更多
关键词 混合气体 输运特性 气体动理论统一算法 激波结构
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最小熵增准则在激波/边界层干扰分析中的应用
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作者 王成鹏 郝晨光 +7 位作者 李昊 薛龙生 焦运 吴思雨 马张煜 袁野 李伟俊 侯普晨 《航空学报》 北大核心 2025年第8期93-112,共20页
激波与边界层干扰(SWBLI)广泛存在于高速飞行器内外流场中,具有多尺度、非线性、非定常等特征,引起局部热流和压力的跃升,给流场品质及结构强度带来影响。详细探讨了激波与边界层干扰的波系结构特征与壁面压升规律,通过对几种典型场景... 激波与边界层干扰(SWBLI)广泛存在于高速飞行器内外流场中,具有多尺度、非线性、非定常等特征,引起局部热流和压力的跃升,给流场品质及结构强度带来影响。详细探讨了激波与边界层干扰的波系结构特征与壁面压升规律,通过对几种典型场景下的激波结构分析,加深对这类复杂流动的机理认识。首先,简述了无黏激波反射理论、自由干扰理论、最小黏性耗散准则等理论模型的研究进展;随后,对比了基于边界层结构与基于激波干扰结构的两种建模思想;最后,着重阐述了最小熵增准则在求解激波与边界层干扰复杂流动问题中的应用。结果表明:最小熵增准则(MEP)作为热力学第二定律的延伸,应用于含分离流动的复杂激波干扰流场时具有较大的优势,在激波结构、压升规律的分析和预测方面表现出与试验结果较好的一致性,为激波与边界层干扰相关的基础科学问题提供了新的解决思路。 展开更多
关键词 可压缩流 激波/激波干扰 激波/边界层干扰 最小熵增准则 流场结构分析
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高马赫数条件燃烧室斜爆轰波起爆过程试验
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作者 张晓源 李进平 +3 位作者 马虎 张仕忠 陈硕 陆星宇 《航空学报》 北大核心 2025年第9期230-240,共11页
斜爆轰技术具有结构简单、燃烧效率高和比冲高等优点,而试验条件的局限性限制了对斜爆轰的深入理解和该技术的进一步发展。基于反向爆轰驱动激波风洞直连试验系统,模拟了飞行高度30 km、马赫数9的来流条件,针对乙烯燃料进行了25°... 斜爆轰技术具有结构简单、燃烧效率高和比冲高等优点,而试验条件的局限性限制了对斜爆轰的深入理解和该技术的进一步发展。基于反向爆轰驱动激波风洞直连试验系统,模拟了飞行高度30 km、马赫数9的来流条件,针对乙烯燃料进行了25°斜劈的斜爆轰波起爆试验。该系统通过激波管产生高温高压空气,经喷管加速后进入燃烧室,待空气流场建立后喷入燃料,与空气混合起爆。对斜爆轰波的结构特征及起爆过程进行观测与分析,在斜劈处形成了清晰的斜爆轰波系结构,准确识别出斜激波、斜爆轰波、横波和三波点等特征。在波后存在高亮度区域,表明了强烈化学反应的发生。斜爆轰波在试验中稳定时间约为6 ms,角度保持在80°±2°范围内,且试验具有良好的重复性。分析表明,试验中获得的斜爆轰波位于极曲线的过驱动强解区域。试验展示了斜爆轰波的起爆过程:燃料喷注前,斜劈前首先形成稳定的斜激波;燃料喷注后,斜激波与分离激波的交汇位置触发混合燃气起爆;起爆后形成的爆轰波面由化学反应支撑,逐渐向前推进,波面长度不断增加,直至达到稳定状态。最终,激波管内反射激波产生的高压破坏了斜爆轰波结构。 展开更多
关键词 斜爆轰 激波 起爆 波系结构 激波风洞
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