FFT

自己写了一个二维Euler方程的间断有限元程序 上次发了一个三角形单元的程序 因为不是曲边单元 所以在圆柱后面容易形成涡 现在把程序改为曲边四边形单元了 没有涡出现 单元是8节点四边形单元 节点编号顺序是 1 5 2 6 3 7 4 8 也就是四个角点依次 是1 2 3 4 然后是边的中点编号 5 6 7 8. 时间推进采用 Runge-Kutta 方法 数值通量采用全局Lax-Friedrichs通量 仍然不能捕捉激波 因为没有做重构或者加人工粘性 等这个做出来了 再发一次。 程序没有进行优化 比如说内存的消耗没有优化 比如直边单元的边界积分仍然采 用了曲边的积分方法 增加了计算量 比如面积分、线积分都是采用的是Gauss- Legendre-Lobatto积分 积分精度会比一般的Gauss-Legendre积分精度低一阶 等 等问题。 二维的 纯属交流性质 就没有考虑这些问题 ^_^ 如果物面全部是直边 那么只要改变一个参数N 就可以获得不同的计算精度 且具 有谱精度 因为单元的节点是Gauss-Legendre-Lobatto积分点。 其实就是谱元法 （物面是曲边的情况我不清楚是不是也可以通过提高基函数的阶数 也就是增加N 来提高计算精度）(Wrote a two-dimensional Euler equations with discontinuous finite element program Last made ​ ​ a triangular element of the program, not curved edge unit is so easy to form a vortex in the cylinder behind the Program to curved edge quadrilateral element vortices appear Unit is the order of 8-node quadrilateral element node number is 15,263,748 which is the four corners of the points in turn Is 1234 and then the side of the midpoint of the number 5678. Time promote the use of Runge-Kutta method Numerical flux of the overall situation of Lax-Friedrichs, flux Still can not capture the shock wave did not do the reconstruction or artificial viscosity do it Zaifayici. The program is not optimized for example, memory consumption is not optimized such as straight-edge boundary integral of the unit is still mining Integral method to increase the amount of computation such as surface integral with a curved edge, the line integral using the Gauss- The Legendr)

说明：  一维黎曼问题，一维问题，即激波管问题，是一个典型的一维可压缩无黏气体动力学问题，并有 解析解。对它采用二阶精度两步差分格式进行数值求解。(Riemann problem, One dimensional problem, the shock tube problem, is a typical one-dimensional compressible non viscous gas dynamic problem with analytic solutions. It is solved numerically by two order two step difference scheme.)

幻方 (magic cube )

基于D2Q9模型的LBM程序，用于计算方腔驱动流，对应何亚玲《格子Boltzmann方法的理论及应用》一书的源码(LBM D2Q9 model-based program used to calculate the square cavity driven flow, which corresponds He Yaling " Lattice Boltzmann Method Theory and Applications," a source book)

一种借助lowtran7计算大气透过率和目标辐射的软件平台ART2100(A program that used for calculate air transferrate and object randience based on lowtran7)

PMV，的热舒适指标计算程序VB编码，可供参考(PMV, thermal comfort index calculation program VB code, for reference)

计算器编程代码，便于需要编程计算器的学员查询相关代码(Calculator programming code, to facilitate students in need of programming calculator related code)

膜渗透 FUENT UDF 气液两相流 (Gas-liquid two-phase flow membrane permeation FUENT UDF)

BICG算法，是Krylov子空间的迭代方法之一(The BICG algorithm is one of the Krylov subspace iteration method)

比Windows自带的高级一点的计算器，能将整个表达式输入，然后求值。 这个程序要求读者具备编译原理的一些知识。 (Advanced calculator than Windows built, the whole expression input can be then evaluated. This program requires the reader to have some knowledge of compiler theory.)