共查询到20条相似文献,搜索用时 109 毫秒
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(杨伯源)(李勇)NUMERICALSIMULATIONOFFLOWOFHIGHLYVISCOELASTICFLOWINTHREE-DIMENSIONALVARYINGTHICKSLITCHANNEL¥YangBoyuan;LiYong(Depart... 相似文献
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LARGEDEFLECTIONPROBLEMOFTHINORTHOTROPICCIRCULARPLATEONELASTICFOUNDATIONWITHVARIABLETHICKNESSUNDERUNIFORMPRESSURE(王嘉新)(刘杰)LARG... 相似文献
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NUMERICALSIMULATIONOFTHREEDIMENSIONALTURBULENTFLOWINSUDDENLYEXPANDEDRECTANGULARDUCTNUMERICALSIMULATIONOFTHREEDIMENSIONALTURBU... 相似文献
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MOTIONEQUATIONSOFMULTILAYEREDELASTICELECTROCONDUCTIVEPLATESINAMAGNETICFIELDGouXing-hua(苟兴华)(SichuanUniversity,Chengdu)ZhangFa... 相似文献
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QUASI-FLOWCORNERTHEORYONLARGEPLASTICDEFORMATIONOFDUCTILEMETALSANDITSAPPLICATIONSHuPing(胡平)LiuYuqi(柳玉启)GuoWei(郭威)TaiFeng(台风)(R... 相似文献
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周叮 《应用数学和力学(英文版)》1996,17(8):773-779
ANANALYTICALSOLUTIONOFTRANSVERSEVIBRATIONOFRECTANGULARPLATESSIMPLYSUPPORTEDATTWOOPPOSITEEDGESWITHARBITRARYNUMBEROFELASTICLINE... 相似文献
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GREEN'SFUNCTIONSOFTWO-DIMENSIONALANISOTROPIC BODY WITH A PARABOLIC BOUNDARY(胡元太)(赵兴华)GREEN'SFUNCTIONSOFTWO-DIMENSIONALANISOTROP?.. 相似文献
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郭兴明 《应用数学和力学(英文版)》1996,17(5):445-450
CHARACTERISTICSOFSUBDIFFERENTIALSOFFUNCTIONS(郭兴明)CHARACTERISTICSOFSUBDIFFERENTIALSOFFUNCTIONS¥GuoXingming(ReceivedJune16,1995... 相似文献
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NUMERICALMODELINGOFTHEINITIALSTAGEOFTHEGENERATIONOFUNSTEADYVORTICESFROMSHARPCORNERINPLANECOMPRESSIBLEFLOWHuangDun(黄敦)(Depart.... 相似文献
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A UNIFORMLY CONVERGENT DIFFERENCE SCHEME FOR THE SINGULAR PERTURBATION PROBLEM OF A HIGH ORDER ELLIPTIC DIFFERENTIAL EQUATION 总被引:1,自引:0,他引:1
AUNIFORMLYCONVERGENTDIFFERENCESCHEMEFORTHESINGULARPERTURBATIONPROBLEMOFAHIGHORDERELLIPTICDIFFERENTIALEQUATION(刘国庆)(苏煜城)AUNIFO... 相似文献
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舰船海底地震波形成机理的理论分析 总被引:1,自引:0,他引:1
航行舰船是一个很大的振动和噪声源,其振动和噪声引起的压力波经由流体介质传播到海底,引起海底岩层振动,产生弹性波并向远处传播,这种航行舰船在海底引起的弹性波称为舰船海底地震波。舰船海底地震波可用于识别舰船目标,作为水中武器的目标探测信号。基于波动理论,得到了舰船引起海底地震波的波动方程和有限元数值计算模型。利用该模型,对二维半无限空间层状海洋环境在水压场和极低频点声源作用下的海底地震波信号进行了数值模拟,得到了远场海底表面处加速度和水压的时域频域信号。结果表明,在二维半无限空间层状海洋环境条件下,舰船远场海底地震波主要由舰船极低频的噪声辐射引起,主要频率范围在1-7Hz。 相似文献
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高速列车致声屏障在极短的时间内受到交变气动力作用,一旦声屏障因强度或疲劳破坏而失效,有可能危及行车安全,因此准确评估高速列车致声屏障的脉动风压分布是结构设计需考虑的关键要素.利用数值风洞技术,模拟了道路及桥梁两侧分别布置5m、3.5m高声屏障,350km/h的列车通过时致声屏障的极值风压分布特性.研究结果表明列车驶过声屏障会产生气流挤压的正压波及气流填充的负压波,正压数值较负压数值大;极值风压随声屏障高度的增加而减小,且列车中心与声屏障的距离、声屏障的高度都会明显减弱极值风压的数值;两列车的交会相比单列车的通过,会更明显地挤压声屏障区域内的气流,从而在声屏障上产生更大的极值风压,且随着列车与声屏障距离的靠近,挤压增大极值风压的特性表现更为明显.最终通过选取京沪高铁试验段,进行相关的现场高速列车致声屏障极值风压试验测试,试验结果验证了数值模拟结果的准确性. 相似文献
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金属导爆索的爆炸水声特性 总被引:1,自引:0,他引:1
为了研究金属导爆索的水声特性,进行了水下爆炸压力测试和气泡脉动实验,获得了金属导爆索水下爆炸冲击波传播和衰减特性及气泡脉动特性.研究了金属导爆索水下爆炸的声压级、声持续时间、混响效应和功率谱特性,结果表明:(1)金属导爆索水下爆炸声压级较高,具有很强的声功率;(2)金属导爆索水下爆炸后产生的气泡脉动和随后产生的大量小气... 相似文献
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In this study, an integrated flow simulation and aeroacoustics prediction methodology is applied to testing a sound control
technique using porous inserts in an open cavity. Large eddy simulation (LES) combined with a three-dimensional Ffowcs Williams–Hawkings
(FW–H) acoustic analogy is employed to predict the flow field, the acoustic sources and the sound radiation. The Darcy pressure
– velocity law is applied to conceptually mimic the effect of porous media placed on the cavity floor and/or rear wall. Consequently,
flow in the cavity could locally move in or out through these porous walls, depending on the local pressure differences. LES
with “standard” subgrid-scale models for compressible flow is carried out to simulate the flow field covering the sound source
and near fields, and the fully three-dimensional FW–H acoustic analogy is used to predict the sound field. The numerical results
show that applying the conceptual porous media on cavity floor and/or rear wall could decrease the pressure fluctuations in
the cavity and the sound pressure level in the far field. The amplitudes of the dominant oscillations (Rossiter modes) are
suppressed and their frequencies are slightly modified. The dominant sound source is the transverse dipole term, which is
significantly reduced due to the porous walls. As a result, the sound pressure in the far field is also suppressed. The preliminary
study reveals that using porous-inserts is a promising technology for flow and sound radiation control. 相似文献
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可爆性气体爆炸极限和爆燃转变成爆轰的研究 总被引:15,自引:3,他引:15
我们成功地研制了长为6.6m、内径为100mm的柱形爆炸激波管。利用此激波管我们研究了氢气和氧气混合物的爆炸特性。研究表明:氢气和氧气混合物的可爆性极限为25%H2至84%H2(体积比);混合物起爆的临界初始压力P0c近似与混合物的浓度无关。我们还用石英传感器技术测量了混合物从爆燃转变为爆轰的过程(DDT),确定了爆炸速度、爆炸压力与混合物初始压力P0的关系。爆燃波速度D和压力P快速增加,并且DG0(声速)时,爆燃波能转变成爆轰。爆燃波速度D和压力P衰减时,爆燃波将熄灭。氢氧混合物浓度接近上限时,爆燃向爆轰转变时的爆轰呈过激励状态,然后逐渐趋于正常爆轰。C-J理论可近似预估气体爆轰参数。 相似文献
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《European Journal of Mechanics - B/Fluids》2000,19(5):637-652
The sound field in a circular pipe generated by a concentric jet flow entering the pipe is studied. In the first case the air flow enters the pipe through a convergent nozzle only. In the second case a short diffuser is attached to the nozzle. When the diffuser half angle is small enough to ensure attached flow conditions, the sound pressure level in the duct is reduced over the entire frequency range measured. When the diffuser angle is increased up to the point where flow separation occurs, an increase in the duct sound pressure level is observed. It is shown by means of cross-correlation measurements involving the unsteady wall pressures in the diffuser and the sound pressure in the duct that the increased sound levels are in fact caused by the flow separation in the diffuser. 相似文献