共查询到20条相似文献,搜索用时 171 毫秒
1.
VISAR测速中的信号丢失及丢失条纹数的确定 总被引:5,自引:2,他引:3
论述了VISAR测速中信号频率与被测速度增量的关系和光电倍增管、数字示波器所能响应的最高速度增量。分析了信号丢失的原因,给出了丢失条纹数的确定方法。最后对VISAR应用中如何正确选择条纹常数提出了建议。 相似文献
2.
THECOMPRESSIONLSESTIMATEOFREGRESSIONCOEFFICIENTINMULTIVARIATELINEARMODELChenShi-ji(陈世基)(Dept.ofMathematics,FUjianNormalUniver... 相似文献
3.
激光干涉测速技术在爆轰实验中的应用 总被引:2,自引:0,他引:2
用四探头VISAR系统测量了铜管外表面在冲击波作用下的膨胀速度以及各种材料(C11,Al,Fe,玻璃)平面飞片的自由表面速度。是的圆筒壁面径向膨胀速度大于1400m/s,平面飞片自由面运动速度大于5500m/s,各被测样品的速度-时间曲线反映了物体的连续运动过程。 相似文献
4.
秦元勋 《应用数学和力学(英文版)》1995,16(7):611-614
RELATIVISTICABSOLUTENESSOFTIME-SPACE-MOVINGMASSChinYuanshun(秦元勋)(InstituteofAppliedMathematicsAcademiaSinicaChina,Beijing1000... 相似文献
5.
田立新 《应用数学和力学(英文版)》1994,15(10):973-980
THEMAXIMUMDISSIPATIVEEXTENSIONOFSCHRODINGEROPERATORTianLi-xin(田立新)(DepartmentofMathematicsandPhysics,JiangsuInstituteofTechno... 相似文献
6.
INITIALBOUNDARYVALUEPROBLEMSFORACLASSOFNONLINEARINTEGRO-PARTIALDIFFERENTIALEQUATIONSCuiShang-bin(崔尚斌)(Dept.ofMath.,LanzhouUni... 相似文献
7.
张宝善 《应用数学和力学(英文版)》1994,15(12):1177-1186
AMODIFIEDMETHODOFAVERAGINGFORSOLVINGACLASSOFNONLINEAREQUATIONSZhangBao-shan(张宝善)(DeparimentofMaih.,XuzhouTeachersCollege,Xuzh... 相似文献
8.
AUNIFORMLYVALIDASYMPTOTICSOLUTIONOFTHENAVIER-STOKESEQUATIONSQinSheng-li(秦圣立)ZhangAi-shu(张爱淑)(Dept.OfPhysics,QufuTeachersUnive... 相似文献
9.
DISSIPATIVEEFFECTSOFANISOLATEDBUBBLEINWATERONTHESOUNDWAVEHunagJing-quan(黄景泉)LiFu-xin(李福新)(NorthwesternPolytechnicUniversity,X... 相似文献
10.
ITERATIVEPROCESSFORLIPSCHITZLOCALSTRICTLYPSEUDOCONTRACTIVEMAPPINGSDengLei(邓磊)(ChongqingTeacher'sCollege,Yongchuan,Chongqing)D... 相似文献
11.
爆炸箔起爆器小尺寸飞片速度测试 总被引:3,自引:0,他引:3
设计了一套爆炸箔起爆装置,通过精确控制桥箔-飞片-加速腔三者的定位,在飞片表面镀一定厚度的铝膜(铝膜的质量与飞片的质量相比可忽略),合理选择VISAR探头的工作距离和与干涉腔延迟时间相关的条纹常数,屏蔽测试系统以及加设滤光片等,利用VISAR测试技术有效解决了小尺寸飞片速度的测试问题。给出了两种尺寸0.7 mm0.025 mm和0.5 mm0.025 mm飞片的速度测试结果。结果表明,采取新的措施后,获得了信噪比好、能正确反映爆炸箔起爆器驱动飞片物理过程的信号和飞片速度历史。 相似文献
12.
13.
《International Journal of Multiphase Flow》1986,12(3):405-425
Measurements of phase-distribution phenomena were made for fully developed. turbulent air/water two-phase flow in a vertical isosceles-triangular test section. These measurements included the local void-fraction and liquid-phase velocity using an RF-excited local impedance probe and Pitot tube. respectively. It was found that substantial lateral “void drift” occurred. with the vapor phase collecting in the more open. high-velocity. region of the test section. 相似文献
14.
15.
The principles of the design of a fast-response DC-coupled ionisation probe and associated electronic circuit are described for the measurement of the mean and fluctuating components of the ion concentration in the reaction zones of stationary and transient flames. The performance of the ionisation probe is evaluated by bench tests and with measurements of ion current mean and fluctuating levels in laminar and turbulent premixed flames and in the combustion chamber of a spark ignition engine. The results demonstrate the wide frequency bandwidth, good spatial resolution and electronic noise immunity of the ionisation probe, making it suitable for a host of combustion applications. 相似文献
16.
Probe measurements were performed in the flow field produced by injection of helium or air into a supersonic airstream. The
injectant was seeded with water and Rayleigh scattering was used to image the injectant plume. The region of the flow containing
injectant–air mixture is seen to be highly unsteady, leading to the intermittent presence of injectant in certain regions.
The intermittency is inferred. It is shown that bias errors can occur when the probe data is analyzed by techniques which
assume steady flow. A technique for relatively bias-free analysis utilizing the intermittency measurements is presented and
the bias errors are estimated. The gas-sampling probe is shown to measure the mass-weighted-mean mass fraction of helium,
which is significantly less than the simple mean. A new measure of mixing efficiency obtained from the combined probe and
intermittency measurements is discussed.
Received: 2 February 1996/Accepted: 2 December 1996 相似文献
17.
An experimental study on the efficiency of transpiration cooling in laminar and turbulent hypersonic flows 总被引:1,自引:0,他引:1
An experimental study on the efficiency of transpiration cooling in hypersonic laminar and turbulent flow regimes is carried
out in the Hypersonic Windtunnel Cologne with a focus on the aerothermal problems downstream of the cooled model part. The
model is made of a material of low thermal conductivity (PEEK) with an integrated probe of a porous material. The experimental
setup allows the direct comparison of the thermal behavior of transpiration cooling to a well-defined and radiatively cooled
reference surface. Experiments are performed at Mach number of 6 and two different Reynolds numbers. Air, argon and helium
are used as coolants at various flow rates, in order to identify the influence of coolant medium on cooling efficiency. The
cooling efficiency of air and argon is comparable. Helium provides significantly higher cooling efficiency at the same blowing
ratio, i.e. same coolant mass flow rate. The experimental data shows that the efficiency of the transpiration cooling in turbulent
flows is much lower than in laminar flow. 相似文献
18.
Accurate measurements of local time-averaged two-phase flow parameters is of fundamental importance for the evaluation of two-phase flow models as well as for the development of closure relations used in the two-fluid model. For cross-calibration purposes, we compared the measurements of local-time-averaged two-phase flow parameters using a four-sensor conductivity probe developed by the TRSL (Thermal-hydraulics and Reactor Safety Laboratory) at Purdue University, and a four-sensor optical probe developed by the CEA (French Atomic Energy Commission). A system coupling methodology was also performed in order to isolate the effects of each instrumentation's components, i.e., probe, acquisition, thresholding, and processing effects. Experimental results have shown a reasonable agreement in the local void fraction, local bubble velocity, and local interfacial area concentration measurements comparisons. However, it is shown that particular attention must be given to the sensor probe design in order to get accurate measurements. 相似文献
19.
Interfacial area concentration (IAC) is one of the most important parameters in the two-phase flow models. Five-sensor probe method is a useful measurement technique to measure an IAC. It is essentially based on the four-sensor probe method but it is improved by adapting one more sensor. The passing types of the interfaces through the sensors are classified into four categories and independent methods are applied to the interfaces belonging to each category. To verify the applicability of the five-sensor probe method, benchmarking tests are performed for a rectangular visual channel by using the photographic method. The bubble velocity, void fraction, and Sauter mean diameter measured by the probe are also benchmarked. This paper also includes the design of the five-sensor conductivity probe, the IAC measurement method, the signal processing procedure of the probe signal and the data analysis method by photography. 相似文献
20.
The design and operational characteristics of a 12-sensor hot wire probe for three-dimensional velocity–vorticity measurements
in turbulent flow fields is described and discussed. The performance of the probe is investigated in comparison with X-sensor
probe measurements in the near field of a rectangular turbulent jet with aspect ratio 6. Measurements have been conducted
at Reynolds number Re
D
= 21,000 at nozzle distances of x/D = 1, 3, 6 and 11, where D is the width of the nozzle. The results obtained with the 12-sensor probe compare well to the results of the X-sensor probe.
Distributions of mean and fluctuating velocity–vorticity fields are presented and discussed. Among the results the most prominent
is the experimental confirmation of the high levels of fluctuating vorticity in the shear layers. 相似文献