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61.
斜变换ST的演化生成与快速算法 总被引:9,自引:0,他引:9
1.引言 含有“斜”基向量的正交变换(斜变换 ST)概念是由 Enomoto & Shibata(1971)提出的[1].斜向量是一个在其范围内呈均匀阶梯下降的离散锯齿波形.对于亮度逐渐改变的图象,用斜向量来表示是适合的. Enomoto & Shibata仅考虑了斜向量长度为 4和 8的情况.Pratt等人利用递推性将 ST推广到 N= 2m阶的情形,给出了 ST的一般定义[2],并与其它变换进行了比较[3].ST已成功地用在图象编码上,而且在非正弦类交换编码的应用中,斜变换的效果最好[2,3]. Ah… 相似文献
62.
63.
A unified incompressible lattice BGK model and its application to three-dimensional lid-driven cavity flow 下载免费PDF全文
A unified lattice Bhatnagar-Gross-Krook (ILBGK) model iDdQq for the incompressible Navier-Stokes equation is presented. To test its efficiency, the lid-driven cavity flow in three-dimensional space for Reynolds number Re=3200 and span aspect ratio SAR=1, 2 and 3 is simulated in detail on a 48×48×(48×SAR) uniform lattice using the model. The test results agree well with those in previous experiments and numerical works and show the efficiency and strong numerical stability of the proposed ILBGK model. 相似文献
64.
Lattice—BGK simulation of a two—dimensional channel flow around a square cylinder 总被引:9,自引:0,他引:9 下载免费PDF全文
The confined flow around a square cylinder mounted inside a
two-dimensional channel (blockage ratio $\be=1/8$) was investigated in
detail by a newly developed incompressible nonuniform lattice-BGK
model. It is found that the vortex shedding behind the cylinder
induces periodicity in the flow field, and the periodicity of the
flow will lose for $Re>$300. A detailed analysis for a range of
Reynolds numbers between 1 and 500 was presented. Quantitative
comparisons with other methods show that the model gives accurate
results for complex flows. 相似文献