排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
基于VisIt的全球科学数据并行可视化——以大气温度场为例 总被引:1,自引:0,他引:1
针对当前大规模全球科学数据可视化中存在的单机可视化数据量有限、从底层开发并行可视化系统难度大等问题,该文基于分布式环境和VisIt,提出了一种简便、开放而又有效的大规模全球科学数据可视化方法。介绍了VisIt的体系结构及运行机制,给出了自定义数据的并行可视化方法;并基于NCEP数据集及全球空间格网,在小规模集群环境下实现了小粒度适应性球体退化八叉树格网(SDOG)下的全球大气温度场的并行可视化。VisIt的并行可视化性能测试结果表明:通过增加计算节点,VisIt能有效摆脱传统单机可视化对数据量的限制,可实现大规模全球科学数据的并行可视化。 相似文献
2.
Zhenglu Jiang 《Celestial Mechanics and Dynamical Astronomy》2009,103(1):31-47
In this paper we analyse the relations between a previously described oblate Jaffe model for an ellipsoidal galaxy and the
observed quantities for NGC 2974, and obtain the length and velocity scales for a relevant elliptical galaxy model. We then
derive the finite total mass of the model from these scales, and finally find a good fit of an isotropic oblate Jaffe model
by using the Gauss-Hermite fit parameters and the observed ellipticity of the galaxy NGC 2974. The model is also used to predict
the total luminous mass of NGC 2974, assuming that the influence of dark matter in this galaxy on the image, ellipticity and
Gauss-Hermite fit parameters of this galaxy is negligible within the central region, of radius 0.5R
e. 相似文献
3.
The paper presents a theoretical and an experimental investigation into the buckling of seven oblate hemi-ellipsoidal dome shells under external hydrostatic pressure. Four of the shells were made in glass reinforced plastic and three were made from a thermosetting plastic called solid urethane plastic. All the vessels were tested to destruction. The theoretical study was made with the aid of a non-linear finite element solution, where both geometrical and material non-linearity were allowed for. Good agreement was found between experiment and theory for all the vessels. The very oblate domes failed axisymmetrically. Theoretical convergence was good for the more oblate domes but it was not as good as for the less oblate domes. This may have been because the less oblate domes did not fail in a classical axisymmetric manner as was expected. This work is of much importance in ocean engineering. 相似文献
4.
C. T. F. Ross Bak Hock Huat Tay Boon Chei Chai Min Chong M. D. A. Mackney 《Ocean Engineering》2003,30(5):691-705
The paper reports on a theoretical and an experimental investigation into six GRP hemi-ellipsoidal dome shells, which were tested to destruction under external hydrostatic pressure. All six domes were of oblate shape and of three different aspect ratios. Each aspect ratio consisted of two dome shells, one made from two layers of glass fibre and one made from three layers of glass fibre. The theoretical analysis was via the finite element method where a non-linear theory was used which allowed for both geometrical and material non-linearity. Comparison between theory and experiment was good. 相似文献
5.
M. Xavier James Raj 《Planetary and Space Science》2009,57(1):34-41
A new non-singular analytical theory for the contraction of near-Earth satellite orbits under the influence of air drag is developed in terms of uniformly regular Kustaanheimo and Stiefel (KS) canonical elements using an oblate atmosphere with variation of density scale height with altitude. The series expansions include up to fourth power in terms of eccentricity and c (a small parameter dependent on the flattening of the atmosphere). Only two of the nine equations are solved analytically to compute the state vector and change in energy at the end of each revolution, due to symmetry in the equations of motion. It is observed that the analytically computed values of the semi-major axis and eccentricity are consistent with the numerically integrated values up to 500 revolutions over a wide range of the drag-perturbed orbital parameters. The theory can be effectively used for re-entry of near-Earth objects. 相似文献
6.
基于球体退化八叉树格网的地球系统空间格网(SDOG-ESSG)是地球系统科学与空间信息领域的重要的研究工具和手段。SDOG-ESSG格网码与现有空间参考相互转换的关键问题即球体坐标系与SDOG-ES-SG格网码的正向转换与逆向转换的算法。通过引进6种列-行-层坐标系并导出有关计算公式,借鉴Morton码行列二进制位交错的特性,分别设计了正向转换与逆向转换算法过程,在此基础上,理论分析并实验验证了两算法的时间效率。结果表明,两转换算法非常高效,其时间消耗基本与SDOG-ESSG的主剖次和副剖次呈线性关系,时间复杂度为O(n);在PC环境下,每秒能实现106~107次的转换运算,1次转换相当于101~102次的除法运算。 相似文献
7.
Periodic orbits in the photogravitational restricted problem with the smaller primary an oblate body
In this paper, we have studied periodic orbits generated by Lagrangian solutions of the restricted three body problem when
more massive body is a source of radiation and the smaller primary is an oblate body. We have determined periodic orbits for
fixed values of μ, σ and different values of p and h (μ mass ratio of the two primaries, σ oblate parameter, p radiation parameter and h energy constant). These orbits have been determined by giving displacements along the tangent and normal to the mobile co-ordinates
as defined by Karimov and Sokolsky (in Celest. Mech. 46:335, 1989). These orbits have been drawn by using the predictor-corrector method. We have also studied the effect of radiation pressure
on the periodic orbits by taking some fixed values of μ and σ. 相似文献
8.
9.
Andrew J. Willmott 《地球物理与天体物理流体动力学》2013,107(4):349-351
We present an analytical, idealized yet precise model of the terrestrial gravity field. The model is meant as a basic ingredient of geophysical fluid dynamics (GFD). We explicitly deal with geopotential coordinates, show in what sense horizontal geopotential coordinate surfaces can be approximated by spherical surfaces and thus provide a clear interpretation of the “spherical approximation” of the equations of motion in GFD. The horizontal component of the gravitational force plays a crucial role in the spherical approximation. It is shown that to leading order in the relevant small parameters, the horizontal components of the gravitational force and the centrifugal force cancel each other in the spherical approximation of the geopotential field. 相似文献
10.
We have studied periodic orbits generated by Lagrangian solutions of the restricted three body problem when one of the primaries
is an oblate body. We have determined the periodic orbits for different values of μ, h and A (h is energy constant, μ is mass ratio of the two primaries and A is an oblateness factor). These orbits have been determined by giving displacements along the tangent and normal to the mobile
coordinates as defined by Karimov and Sokolsky (Celest. Mech. 46:335, 1989). These orbits have been drawn by using the predictor-corrector method. We have also studied the effect of oblateness by
taking some fixed values of μ, A and h. As starters for our method, we use some known periodic orbits in the classical restricted three body problem. 相似文献