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A Study of the Weak Shock Wave Propagating over a Porous Wall/Cavity System

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Journal of thermal Science 2005年第4期14卷 329-333页

作者： H.D.KIM S.J.JUNG t.aoki t.SEtOGUCHI School of Mechanical Engineering.Andong National University Songchun-dongAndong 760-746Korea Department of Energy and Environmental Engineering Kyushu University6-1Kasuga-kouenKasugaFukuoka 816-8580Japan Department of Mechanical Engineering Saga University1HonjoSaga 840-8502Japan

the present computational study addresses the attenuation of the shock wave propagating in a duct, using a porous wall/cavity system. In the present study, a weak shock wave propagating over the porous wall/cavity system is investigated with computational fluid dynamics. A total variation diminishing scheme is employed to solve the unsteady, two-dimensional, compressible, Navier-Stokes equations. the Mach number of an initial shock wave is changed in the range from 1.02 to 1.12. Several different types of porous wall/cavity systems are tested to investigate the passive control effects. the results show that wall pressure strongly fluctuates due to diffraction and reflection processes of the shock waves behind the incident shock wave. From the results, it is understood that for effective alleviation of tunnel impulse waves, the length of the perforated region should be sufficiently long.

关键词： compressible flow perforated wall railway tunnel shock wave.

Effect of Duct Geometry on Shock Wave Discharge

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Journal of thermal Science 2006年第4期15卷 349-354页

作者： Y.-H.Kweon Y.Miyazato t.aoki H.-D.Kim t.Setoguchi Department of Energy and Environmental Engineering Kyushu UniversityKasuga 816-8580Japan Faculty of Environmental Engineering The University of KitakyushuKitakyushu 808-0135Japan School of Mechanical Engineering Andong National UniversityAndong 760-749Korea Department of Mechanical System Engineering Saga UniversitySaga 840-8502Japan

this paper describes computational work to understand the unsteady flow-field of a shock wave discharging from an exit of a duct and impinging upon a flat plate. A flat plate is located downstream, and normal to the axis of the duct. the distance between the exit of the duct and flat plate is changed. In the present study, two different duct geometries （i.e., square and cross section） are simulated to investigate the effect of duct geometry on the un-steady flows of a shock wave. In computation, the total variation diminishing （tVD） scheme is employed to solve three-dimensional, unsteady, compressible, Euler equations. Computations are performed over the range of shock Mach number from 1.05 to 1.75. Computational results can predict the three-dimensional dynamic behaviour of the shock wave impinging upon the flat plate. the results obtained show that the pressure increase generated on the plate by the shock impingement depends on the duct geometry and the distance between the duct exit and plate, as well as the shock Mach number. It is also found that for the duct with cross-section, the unsteady loads acting on the flat plate are less, compared with the square duct.

关键词： unsteady flow compressible flow shock wave shock impingement duct geometry

Study on transonic tone in an Axisymmetric Supersonic Nozzle

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Journal of thermal Science 2010年第5期19卷 397-401页

作者： M.Yonamine S.Jung t.aoki Graduate School of Engineering Sciences Kyushu University

this paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent *** noise phenomenon of flow is generated by an emission of 'transonic tones'.the results obtained show that the frequency of a transonic tone,that differs from the frequency of a screech tone due to the shock-cell structures in a jet and originates in the shock wave in the nozzle,increases in proportion to the nozzle pressure *** high-order transonic tone has the directivity in the direction of the *** for the transonic tone's frequency,the separated zone was calculated by using a simple flow model considering the propagating *** results of the model corresponded to the results of this experiment well.

关键词： Compressible Flow Noise Supersonic Flow Shock Wave and transonic Resonance

the Effect of Reflector with Sound-Absorbing Material on Supersonic Jet Noise

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Journal of thermal Science 2005年第1期14卷 22-27页

作者： Y.-H.KWEON M.tSUCHIDA Y.MIYAZAtO t.aoki H.-D.KIM t.SEtOGUCHI Department of Energy and Environmental Engineering Kyushu University Kasuga 816-8580Japan School of Mechanical Engineering Andong National University Andong 760-749Korea Department of Mechanical Engineering Saga University Saga 840-8502Japan

this paper describes an experimental work to investigate the effect of a reflector on supersonic jet noise radiated from a convergent-divergent nozzle with a design Mach number *** the present study,a metal reflector and reflectors made of three different sound-absorbing materials(grass wool and polyurethane foam)were employed,and the reflector size was *** measurement is carried out to obtain the acoustic characteristics such as frequency,amplitude of screech tone and overall sound pressure level(OASPL).A high-quality schlieren optical system is used to visualize the detailed structure of supersonic *** results obtained show that the acoustic characteristics of supersonic jet noise are strongly dependent upon the jet pressure ratio and the reflector *** is also found that the reflector with sound-absorbing material reduces the screech tone amplitude by about 5-13dB and the overall sound pressure levels by about 2-5dB,compared with those of the metal reflector.

关键词： supersonic jet supersonic jet noise screech tone OASPL reflector sound-absorbing material.

2001年春季东亚-北太平洋地区沙尘气溶胶的辐射强迫

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科学通报 2004年第19期49卷 1993-2000页

作者：王宏石广玉 t.aoki 王标 Zhaotianliang 中国科学院大气物理研究所LASG 北京100029 日本气象厅东京3050052日本多伦多大学多伦多M5S1A1加拿大

中国科学院重大国际合作研究项目风送沙尘的形成、输送机制及其对气候与环境的影响期间, 在中国西北部沙漠地区进行了气溶胶采样, 经过成分分析和理论计算, 得出了该地区沙尘气溶胶的主要光学特性. 与其他沙尘模型相比, 源于中国沙漠的... 详细信息

中国科学院重大国际合作研究项目风送沙尘的形成、输送机制及其对气候与环境的影响期间, 在中国西北部沙漠地区进行了气溶胶采样, 经过成分分析和理论计算, 得出了该地区沙尘气溶胶的主要光学特性. 与其他沙尘模型相比, 源于中国沙漠的沙尘气溶胶复折射指数偏低, 对太阳辐射的吸收性较弱, 散射较强, 前向散射偏弱, 后向散射偏强. 将其作为中国和东亚地区沙尘气溶胶光学模型的代表, 模拟了东亚-北太平洋地区2001年春季平均辐射强迫. 计算得出: 该地区大气顶的平均净辐射强迫为-0.943 W·m-2, 其中短波-1.700 W·m-2, 长波+0.759 W·m-2; 地面净辐射强迫为-5.445 W·m-2, 短波-6.250 W·m-2, 长波+ 0.805 W·m-2. 最后给出了东亚-北太平洋地区大气顶和地面的辐射强迫分布.

关键词：沙尘气溶胶辐射强迫北太平洋中国西北部大气净辐射东亚地区地区长波国际合作

the effect of ground and wall on the impulse wave discharged from an open end of a duct

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The effect of ground and wall on the impulse wave discharged...

the 24th International Symposium on Shock Waves

作者： Y.H.Kweon t.aoki Y.Miyazato H.D.Kim t.Setoguchi Kyushu University 6-1 KasugakouenKasugaFukuoka 816-8580JAPAN Andong National University 388 Songchun-dongAndong 760-749KOREA Saga University 1 Honjo-machiSaga 840-8502JAPAN

When a shock wave is discharged from the exit of a duct, complicated unsteady flow field is formed near the exit of a duct. the flow is much more complicated under the ground effects or any other objects near the exit of a duct, such as the circumstance near the exit of the high-speed railway tunnel. the resulting flow is essentially three-dimensional unsteady with the effects of strong compressibility. In the present study, three-dimensional flow fields of the shock wave that is discharged from the exit of a duct are numerically investigated using a CFD method. Computations are carried out in the range below the Mach number of incident shock wave 1.5. the results obtained clearly show that the directivity and magnitude of the impulse wave discharged from the exit of a duct strongly depend upon the Mach number of incident shock wave and are significantly influenced by the effects of ground and wall.

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养殖香鱼弧菌病高渗浸浴免疫方法改进

国外水产 1986年第3期 34-37页

作者： t.aoki 杜佳垠

香鱼(Plecoglossus altivelis)分布于日本、中国(包括台湾省)和朝鲜。该鱼是重要养殖对象。香鱼易患弧菌病,在日本,弧菌病给鱼类养殖业造成严重危害。养殖香鱼免疫可能成为预防弧菌病的重要措施。最近,在日本,养殖香鱼实验免疫已获成功(... 详细信息

香鱼(Plecoglossus altivelis)分布于日本、中国(包括台湾省)和朝鲜。该鱼是重要养殖对象。香鱼易患弧菌病,在日本,弧菌病给鱼类养殖业造成严重危害。养殖香鱼免疫可能成为预防弧菌病的重要措施。最近,在日本,养殖香鱼实验免疫已获成功(Itami 和Kusuda,1978;等)。科学家们所提出的高渗浸浴免疫方法可能有效预防香鱼弧菌病(aoki 和 Kitao,1978;等)。然而,在高渗浸浴免疫后饲养期间,香鱼死亡率很高(aoki 等,1982)。用福尔马林灭活鳗弧菌

关键词：香鱼弧菌病浸浴灭活疫苗鳗弧菌福尔马林防腐剂免疫方法高渗

Assessing efficacy of standard impregnation techniques on die-cast aluminum alloys using X-ray micro-Ct

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China Foundry 2024年第3期21卷 276-286页

作者： Ajith Bandara Koichi Kan Katanaga Yusuke Natsuto Soga Akifumi Koike toru aoki Hamamatsu tSC Chuo Hatsumei Institute322 lida-choMinami-kuHamamatsu435-0028Japan Graduate School of Medical Photonics ShizuokaUniversityJohoku 3-5-1HamamatsuShizuoka432-8561Japan ANSeeN Inc Johoku 3-5-1HamamatsuShizuoka432-8561Japan Research Institute of Electronics ShizuokaUniversityJohoku 3-5-1HamamatsuShizuoka432-8561Japan

Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak *** pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al *** this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCt)and a standard leak *** results demonstrate that the commonly used water leak test is insufficient for determining the sealing ***,micro XCt shows distinct advantages by enabling more comprehensive *** reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in *** effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray *** research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals.

关键词： nondestructive testing Al alloy die-casting vacuum pressure impregnation micro X-ray computed tomography duel-energy X-ray Ct

三角纤维软骨的超短回波时间(UtE)定量MR成像:摆位的差异

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国际医学放射学杂志 2019年第4期 505-506页

作者：吴越 A.Fujisaki t.aoki H.Narimatsu C.Kuwahara A.Nozaki K.Menuki Department of Radiology University of Occupational and Environmental Health

摘要目的比较分别在中立位、腕部尺骨屈曲和前臂内旋位获得的三角纤维软骨（tFC）超短时间回波（UtE）的t2*值。方法对10名健康志愿者使用8通道膝关节线圈在3t

关键词： UtE 三角纤维软骨回波时间 MR