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991.
QU Jianjun YAN Muhong DONG Guangrong ZHANG Hongfa ZU Ruiping TUO Wanquan ZHAO Aiguo XlAO Zhenghua LI Fang & YANG Bao Key Laboratory of Desert Desertification Cold Arid Regions Environmental Engineering Research Institute Shapotou Desert Research Experiment Station Chinese Academy of Sciences Lanzhou China 《中国科学D辑(英文版)》2004,47(6):529-539
~~Wind tunnel simulation experiment and investigation on the electrification of sandstorms~~ 相似文献
992.
993.
We present a simplified method to simulate strong ground motion for a realistic representation of a finite earthquake source burried in a layered earth. This method is based on the stochastic simulation method of Boore (Boore, D. M., 1983, Bull. Seism. Soc. Am. 73, 1865–1894) and the Empirical Greens Function (EFG) method of Irikura (Irikura, K., 1986, Proceedings of the 7th Japan Earthquake symposium, pp. 151–156). The rupture responsible for an earthquake is represented by several subfaults. The geometry of subfaults and their number is decided by the similarity relationships. For simulation of ground motion using the stochastic simulation technique we used the shapping window based on the kinetic source model of the rupture plane. The shaping window deepens on the geometry of the earthquake source and the propagation characteristics of the energy released by various subfaults. The division of large fault into small subfaults and the method for accounting their contribution at the surface is identical to the EGF. The shapping window has been modified to take into account the effect of the transmission of energy released form the finite fault at various boundaries of the layered earth model above the source. In the present method we have applied the correction factor to adjust slip time function of small and large earthquakes. The correction factor is used to simulate strong motion records having basic spectral shape of 2 source model in broad frequency range. To test this method we have used the strong motion data of the Geiyo earthquake of 24th March 2001, Japan recorded by KiK network. The source of this earthquake is modelled by a simple rectangular rupture of size 24 × 15 km, burried at a depth of 31 km in a multilayered earth model. This rupture plane is divided into 16 rectangular subfaults of size 6.0 × 3.75 km each. Strong motion records at eight selected near-field stations were simulated and compared with the observed records in terms of the acceleration and velocity records and their response spectrum. The comparison confirms the suitability of proposed rupture model responsible for this earthquake and the efficacy of the approach in predicting the strong motion scenario of earthquakes in the subduction zone. Using the same rupture model of the Geiyo earthquake, we compared the simulated records from our and the EGF techniques at one near-field station. The comparison shows that this technique gives records which matches in a wide frequency range and that too from simple and easily accessible parameters of burried rupture. 相似文献
994.
Testing the correctness of the sequential algorithm for simulating Gaussian random fields 总被引:2,自引:2,他引:0
X.?EmeryEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2004,18(6):401-413
The sequential algorithm is widely used to simulate Gaussian random fields. However, a rigorous application of this algorithm is impractical and some simplifications are required, in particular a moving neighborhood has to be defined. To examine the effect of such restriction on the quality of the realizations, a reference case is presented and several parameters are reviewed, mainly the histogram, variogram, indicator variograms, as well as the ergodic fluctuations in the first and second-order statistics. The study concludes that, even in a favorable case where the simulated domain is large with respect to the range of the model, the realizations may poorly reproduce the second-order statistics and be inconsistent with the stationarity and ergodicity assumptions. Practical tips such as the multiple-grid strategy do not overcome these impediments. Finally, extending the original algorithm by using an ordinary kriging should be avoided, unless an intrinsic random function model is sought after. 相似文献
995.
DONGSheng GANBuhong HAOXiaoli 《中国海洋大学学报(英文版)》2004,3(1):111-114
1 Introduction InChina ,coastalcitiesaremostlyregionaleconomicdevelopmentcenters.Becauseoftheirspecialgeogra phiclocations ,typhoonsandassociatedstormsurgescauseheavylossesoflivesandproperties.In 1 992 Qing daowasfloodedduetothecoincidenceoftheastrono m… 相似文献
996.
建筑结构抗震研究若干基本问题概述及讨论 总被引:3,自引:1,他引:2
本文介绍和讨论了结构抗震研究中的一些基本问题,包括地震反应分析选择地面运动输入应注意的问题,高层结构地震模拟试验问题和结构地震反应分析中的主要分析方法和存在的问题,最后简要介绍了目前常用结构反应分析程序。 相似文献
997.
To investigate the stability of the bottom boundary layer induced by tidal flow (oscillating flow) in a rotating frame, numerical experiments have been carried out with a two-dimensional non-hydrostatic model. Under homogeneous conditions three types of instability are found depending on the temporal Rossby number Rot, the ratio of the inertial and tidal periods. When Rot < 0.9 (subinertial range), the Ekman type I instability occurs because the effect of rotation is dominant though the flow becomes more stable than the steady Ekman flow with increasing Rot. When Rot > 1.1 (superinertial range), the Stokes layer instability is excited as in the absence of rotation. When 0.9 < Rot < 1.1 (near-inertial range), the Ekman type I or type II instability appears as in the steady Ekman layer. Being much thickened (100 m), the boundary layer becomes unstable even if tidal flow is weak (5 cm/s). The large vertical scale enhances the contribution of the Coriolis effect to destabilization, so that the type II instability tends to appear when Rot > 1.0. However, when Rot < 1.0, the type I instability rather than the type II instability appears because the downward phase change of tidal flow acts to suppress the latter. To evaluate the mixing effect of these instabilities, some experiments have been executed under a weak stratification peculiar to polar oceans (the buoyancy frequency N2 10−6 s−2). Strong mixing occurs in the subinertial and near-inertial ranges such that tracer is well mixed in the boundary layer and an apparent diffusivity there is evaluated at 150–300 cm2/s. This suggests that effective mixing due to these instabilities may play an important role in determining the properties of dense shelf water in the polar regions. 相似文献
998.
999.
《海洋数值模拟》是淮海工学院面向海洋技术专业本科生开设的专业选修课程。以培养海洋科学专业学生的数值模拟技能为目标,以研究海洋环境动力机制为导向,研究了《海洋数值模拟》课程的教学案例,提出了关于该课程建设上的思考,教学实践表明,学生的基本技能得到明显提高,学习兴趣普遍增强。 相似文献
1000.
从动量定理和水量平衡原理出发,以Saint Venant方程为基础推导出自然降雨条件下不同生态措施(即同时考虑变雨强、降雨动量和不同生态措施影响下的坡地径流过程)坡地的径流基本方程。在考虑一般问题定解条件的基础上,采用Preissmann隐式格式对模型进行数值求解。利用3个处理(裸地、百喜草覆盖和百喜草+果树覆盖)、5组实测资料(不同雨型)对模型进行了验证,结果表明3个处理的计算值与实测值的平均相对误差分别为:14.97%、13.59%、15.15%,说明模型的计算结果是可靠的,对于模拟预测自然降雨条件下不同生态措施坡地径流过程是可行的。 相似文献