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991.
欠膨胀超音速射流处于螺旋模式下的中度欠膨胀时,其入射剪切层的激波具有很高强度,激波和剪切层发生了强烈的相互作用,远场辐射的拢动波出现了大间隔、交错的上下行类似螺旋锥面波形图像,该扰动波具有很强的向上游传播的指向性,导致上游噪声高于垂直喷嘴方向的声压级.而在相对压比较低的低度欠膨胀情况下,或高压比下的高度欠膨胀的情形,入射剪切层激波强度相对较弱,远场辐射没有大间隔、交错的上下行远场辐射
关键词:
超音速射流
啸叫
扰动波
激波
剪切层 相似文献
992.
993.
高能强子–强子碰撞中硬软过程的比较分析 总被引:1,自引:1,他引:0
根据QCD中“圆锥定义”来确定喷注,对高能强子-强子碰撞中的硬、软过程作细致的分析.用Pythia产生蒙特卡罗模拟样本,得到的喷注赝快度分布在中心区有平台,喷注内部的粒子密度和横能密度,随离喷注轴的距离指数地下降,比较发现对整个事件样本,单事件平均横动量或最大横动量与多重数是正关联的,而对喷注事件它们是负关联的.引入两个物理量来描述喷注事件的硬、软程度.发现它们与单事件平均横动量是正关联的,而与多重数是负关联的.表明用单事件平均横动量比用多重数能更好地描述喷注事件的硬软程度. 相似文献
994.
Madjid Birouk Thomas Stbler BarryJ. Azzopardi 《Particle & Particle Systems Characterization》2003,20(1):39-46
The primary break‐up of liquid jets in cross flows has been studied experimentally. An open‐circuit wind tunnel was employed in which the airflow was generated by a centrifugal fan. The test section, positioned 3 m downstream of the fan, was made of clear acrylic resin to allow optical access and visualization. The working liquid used in the present experiment was an aero‐engine lubrication oil, which was injected perpendicularly into the air flow, via a nozzle placed in the top wall of the test‐section. The study of the primary break‐up mechanisms of the jet involved three parameters, the oil viscosity, and the jet and air cross flow velocities, which were varied independently. Two different break‐up regimes were observed and identified; arcade break‐up and bag break‐up. These were separated by a transition zone. Transverse and longitudinal (or streamwise) penetrations of the jet before the liquid breakup were also measured. The correlation proposed by Wu et al. to predict the jet transverse penetration before the break‐up of the liquid, as a function of the liquid/airflow momentum‐flux ratio, was found to be applicable only to liquids with low viscosity. An empirical extension to this equation has been produced. 相似文献
995.
We consider an inertialess Newtonian liquid jet in a slenderbody approximation. Recent work has shown that such jets evolvetowards breakup in finite time, and that the asymptotics ofthe breakup is described by a similarity solution. A mathematicalproof of this fact is still lacking. In this note, we give aproof of self-similar breakup asymptotics under an a prioriassumption on the force in the jet. The results provide a partialexplanation for the observed self-similar breakup asymptoticsin Newtonian liquid jets. 相似文献
996.
From the independence of the contour of spectral density of the rotational (orientation) correlation function of a rigid molecular
top of arbitrary symmetry on temperature in the frequency scale based on the reduced time of rotational orientation relaxation
and from the near independence of the rotational contour of vibrational and vibronic absorption bands of dipole transitions
in the same coordinates in a model of “regular diffusion” of the transition oscillator with a classically rotating rigid molecular
top, it is suggested that it is possible to use the halfwidth of the contour for estimation of temperatures. Data are presented
on the halfwidth of 48 contours of bands of A, B, and C types at this frequency for 12 compounds for a temperature range of
from units to 500 degrees of absolute temperature measured experimentally and (for low temperatures) calculated by the quantum
theory.
Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 312–317, May–June, 1997. 相似文献
997.
It is shown that, upon formation of ultrasound jet-cooled var der Waals complexes of polar molecules of 9-cyanoanthracene,
3-aminophthalimide, and 3-amino-N-methylphthalimide with water molecules, pronounced manifestations of isotope substitution
in the ligand molecules take place, which manifest themselves in shifting 0–0-transitions by 5–7 cm−1 and changes in frequencies of intramolecular vibrations. Spectroscopic effects of isotope substitution of atoms of the amino
group are established for substituted phthalimides. We propose a new mechanism of the effect of isotope substitution on frequencies
of electronic transitions which cannot be reduced to the known one (realized by means of changes in values of the zero vibrational
energy) and is based instead on the change in the charge density distribution in the molecule.
Belarusian State University, 4, F. Skorina Ave., Minsk 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 2, pp. 148–154, March–April, 1997. 相似文献
998.
Relative populations of the excited levels for Cr(I), Cr(II), Fe(I) and Fe(II) in the argon plasma flow of an arc two-jet
plasma generator used in spectrochemical analysis were measured. The range of the total energy E of excitation and ionization
was 4.5–8.0 and 12.5–16.0 eV, respectively. It is shown that the populations of atom and ion levels are linear with respect
to energy lower than E∼15 eV. For ionic lines with energy close to 15.5–16.0 eV the line intensities behave anomalously against
equilibrium values. This can be associated with charge transfer between the analyte and argon ions. Deviation of I from LTE
values increases in the plasma zones below and above the site of jet confluence, where the plasma temperature decreases.
A. P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, 1a Favorskii St., Irkutsk,
664033, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 5, pp. 575–581, September–October, 1997. 相似文献
999.
L.A. Surin A.V. Potapov V.A. Panfilov B.S. Dumesh G. Winnewisser 《Journal of Molecular Spectroscopy》2005,230(2):149-152
The b-type rotational transitions of the van der Waals complex, Ne–CO have been measured using the intracavity OROTRON jet spectrometer in the frequency range of 80–115 GHz. The high sensitivity of this technique enabled us to detect all three Ne isotopic modifications of the complex, 20Ne–CO, 22Ne–CO, and 21Ne–CO in natural abundance. The observed and assigned transitions belong to the Q-branch of the K = 1–0 subband and include also R (0) and P (2) lines. The newly obtained data were analysed together with previously observed millimeter-wave b-type and microwave a-type rotational transitions. 相似文献
1000.
We analyze the azimuthal anisotropy of jet spectra due to energy loss of hard partons in quark-gluon plasma, created initially
in nuclear overlap zone in collisions with non-zero impact parameter. The calculations are performed for semi-central Pb-Pb
collisions at LHC energy. 相似文献