共查询到20条相似文献,搜索用时 0 毫秒
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在惯性约束聚变(ICF)实验中,点火靶丸表面(界面)的粗糙度和缺陷所产生的流体力学不稳定性是决定点火成功与否的关键因素之一,设计和研制流体力学不稳定性分解实验用靶是解决该问题的主要技术手段。结合国内外的研究现状和神光-Ⅱ激光装置的特点,设计并研制了一种新型柱状激波管。该靶型由三种介质组成,分别为调制聚苯乙烯(CH)圆片、柱状碳气凝胶(CRF)和CH微套管。调制CH圆片和柱状CRF通过微加工技术装配到CH微套管内,封装后形成柱状激波管。介绍了该靶型的设计原理和详细的制备工艺,并对相应的靶参数进行了测量。结果表明:柱状CRF气凝胶具有较好的成型性,长度、直径和密度分别为1000μm、730μm和250mg·cm-3;CH圆片的厚度和直径分别为15μm和730μm,表面调制图形的周期和峰谷差分别为100μm和4.3μm;实验得到的柱状激波管的轴向和径向最大装配误差分别为2μm和3μm。 相似文献
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在惯性约束聚变(ICF)实验中,点火靶丸表面(界面)的粗糙度和缺陷所产生的流体力学不稳定性是决定点火成功与否的关键因素之一,设计和研制流体力学不稳定性分解实验用靶是解决该问题的主要技术手段。结合国内外的研究现状和神光-Ⅱ激光装置的特点,设计并研制了一种新型柱状激波管。该靶型由三种介质组成,分别为调制聚苯乙烯(CH)圆片、柱状碳气凝胶(CRF)和CH微套管。调制CH圆片和柱状CRF通过微加工技术装配到CH微套管内,封装后形成柱状激波管。介绍了该靶型的设计原理和详细的制备工艺,并对相应的靶参数进行了测量。结果表明:柱状CRF气凝胶具有较好的成型性,长度、直径和密度分别为1000 m、730 m和250 mgcm-3;CH圆片的厚度和直径分别为15 m和730 m,表面调制图形的周期和峰谷差分别为100 m和4.3 m;实验得到的柱状激波管的轴向和径向最大装配误差分别为2 m和3 m。 相似文献
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A theoretical investigation of the subcritical dynamics of typical fluid-structure interactions is carried out by applying the linear non-modal operators theory combined with direct numerical simulations. The cases of thin panel exposed to subsonic and supersonic fluid flows and pipe conveying a fluid are considered. In order to make the problem tractable for the rather wide range of cases, simple pressure models are employed, where the relevant instability is essentially of modal-coalescence type. Transient energy amplifications, here termed optimal and global, are found, which exhibit low-frequency oscillations corresponding to the continuous extraction/release of energy from/to the fluid. The low frequency is always related to the spacing between the imaginary parts of the coupling eigenvalues, which represent essentially the non-normal part of the spectrum. This suggests that the periodic transfers of energy along the route to the instability can be predicted by a simple model of damped forced vibrations. Although the major findings are obtained with crude pressure models, the authors’ opinion is that most of the effects discussed in the paper should survive to the use of flow dynamics modeling based on full Navier-Stokes equations, at least at high Reynolds number flows. 相似文献
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N. N. Romanova O. G. Chkhetiani I. G. Yakushkin 《Journal of Experimental and Theoretical Physics》2016,122(5):902-914
The problem of the development of shear instability in a three-layer medium simulating the flow of a stratified incompressible fluid is considered. The hydrodynamic equations are solved by expanding the Hamiltonian in a small parameter. The equations for three interacting waves, one of which is unstable, have been derived and solved numerically. The three-wave interaction is shown to stabilize the instability. Various regimes of the system’s dynamics, including the stochastic ones dependent on one of the invariants in the problem, can arise in this case. It is pointed out that the instability development scenario considered differs from the previously considered scenario of a different type, where the three-wave interaction does not stabilize the instability. The interaction of wave packets is considered briefly. 相似文献
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L. S. Vasil’ev 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(11):1525-1527
The features of diffusion mass transfer phenomena in metals under shock conditions are considered. The diffusion fluxes arising
at severe plastic deformation of material are determined. It is shown that under certain conditions the impurity diffusion
from the outer surface into the metal bulk may evolve as a wave process, at which the mass transfer occurs in the form of
ordered atomic motion through the lattice. The diffusion wave propagation velocity of is determined. 相似文献
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We report on a new class of electromagnetically driven fluid interface instability. Using the optical radiation pressure of a cw laser to bend a very soft near-critical liquid-liquid interface, we show that it becomes unstable for sufficiently large beam power P, leading to the formation of a stationary beam-centered liquid microjet. We explore the behavior of the instability onset by tuning the interface softness with temperature and varying the size of the exciting beam. The instability mechanism is experimentally demonstrated. It simply relies on total reflection of light at the deformed interface whose condition provides the universal scaling relation for the onset P(S) of the instability. 相似文献
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Abstract PbSe/SnSe superlattice, phase transition, high pressure, SR x-ray diffraction) Synchrotron x-ray diffraction experiments have revealed successive phase transitions in epitaxially-grown PbSe/SnSe superlattices. The transition pressures from the low-pressre cubic B1- to the high-pressure orthorhombic B16-type structures are observed to vary systematically depending upon thickness of the PbSe layer. For example, a [PbSe(36A)/SnSe(12A)]19, with the B1 structure in both layers stabilized in its asgrown state, undergoes the [B1/B1]-to-[B1/B16] and [B1/B16]-to-[B16/B16] structural transitions at 1.9 and 3.8GPa, respectively. This result is in contrast to their bulk data that the B1-to-B16 transition takes place at 5.3GPa in PbSe while the B16 phase is stable in SnSe at atmospheric pressure. 相似文献
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《Physics letters. A》2006,359(6):681-684
We show that instability may be arisen when the large-scale waves propagate in the ozone layer of Earth's atmosphere. The instability criterion suitable both for the acoustic waves and for the Rossby waves is found. Moreover, the possibility of the spatially located dissipative Rossby vortical structures formation in this layer is established. 相似文献
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Nonequilibrium processes in condensed media. Part 2. Structural instability induced by shock loading
In the first part of the work, we described our concept of shock wave processes, which is based on nonlocal nonequilibrium transport theory, and an associated mathematical elastoplastic wave model that allows for inertial properties, structural changes, and variation in mechanical properties of solid-state materials under shock loading. In the second part of the work, it is demonstrated that the energy exchange between the scales of dynamic deformation is defined by the relation between the characteristics measurable in real time: the mesoscale mass velocity variation and the mass velocity defect due to loss of the energy expended in structure formation. An internal criterion is found for the transition of a dynamically deformed material to structural instability. 相似文献
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V. Balédent 《高压研究》2016,36(3):371-380
ABSTRACTWe report here on the application of Resonant Inelastic X-ray Scattering (RIXS) in correlated electrons systems under pressure. Thanks to its bulk sensitivity and superior resolving power, RIXS appears as a powerful spectroscopic technique to unravel the local electronic and magnetic properties of materials at extreme conditions. The method is illustrated in vanadium-oxides- and Fe-based superconductors at high pressure. 相似文献
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