{"id":1943,"date":"2022-11-10T08:10:00","date_gmt":"2022-11-10T08:10:00","guid":{"rendered":"http:\/\/81.70.49.155\/?p=1943"},"modified":"2022-11-10T08:10:00","modified_gmt":"2022-11-10T08:10:00","slug":"lbm%e9%80%9a%e9%81%93%e6%b5%81-c%e7%89%88-2022%e8%87%aa%e7%bc%96","status":"publish","type":"post","link":"http:\/\/81.70.49.155\/?p=1943","title":{"rendered":"LBM\u901a\u9053\u6d41 C++\u7248 [2022\u81ea\u7f16]"},"content":{"rendered":"

\n\t\"\"\n<\/p>\n

\n\t\n<\/p>\n

\n\t\/\/Program By Yuanqing XU-2022-11-10\n<\/p>\n

\n#include \"stdafx.h\"
\n#include <iostream>
\n#include <cmath>
\n#include <cstdlib>
\n#include <iomanip>
\n#include <fstream>
\n#include <sstream>
\n#include <string>
\nusing namespace std;<\/p>\n

\/\/\u57fa\u672c\u53c2\u6570\uff0c\u9700\u8981\u4ece\u8f6f\u4ef6\u524d\u7aef\u8bbe\u7f6e
\nconst int        Lx = 200;           \/\/x\u65b9\u5411\u7f51\u683c\u6570  \uff08\u53c2\u65701\uff09
\nconst int        Ly = 50;             \/\/y\u65b9\u5411\u7f51\u683c\u6570  \uff08\u53c2\u65702\uff09
\nconst int        MaxT = 3000;     \/\/\u8fed\u4ee3\u6b21\u6570       \uff08\u53c2\u65703\uff09
\nconst int        OutN = 200;        \/\/\u8f93\u51fa\u95f4\u9694       \uff08\u53c2\u65704\uff09
\nconst double  Uin = 0.1;           \/\/\u5165\u53e3\u901f\u5ea6       \uff08\u53c2\u65705\uff09
\ndouble           Re = 30;             \/\/ \u96f7\u8bfa\u6570            (\u53c2\u65706)
\nconst char *const PathD = \"..\\\\DataOut\\\\U_\";  \/\/ \u6570\u636e\u5b58\u653e\u8def\u5f84 (\u53c2\u65707)
\nconst double  pi = 3.14159265;<\/p>\n

\/\/LBM\u53c2\u6570 
\nconst int  Q = 9;          \/\/D2Q9\u6a21\u578b
\ndouble    rho0 = 1.0;
\ndouble    nu = Uin*Ly \/ Re;
\ndouble    tau = 3.0*nu + 0.5;<\/p>\n

\/\/\u53d8\u91cf\u521d\u59cb\u5316
\nint i, j, k, ip, jp, tStep, ii, jj;
\nint e[Q][2] = { { 0, 0 }, { 1, 0 }, { 0, 1 }, { -1, 0 }, { 0, -1 }, { 1, 1 }, { -1, 1 }, { -1, -1 }, { 1, -1 } };
\ndouble w[Q] = { 4.0 \/ 9, 1.0 \/ 9, 1.0 \/ 9, 1.0 \/ 9, 1.0 \/ 9, 1.0 \/ 36, 1.0 \/ 36, 1.0 \/ 36, 1.0 \/ 36 };
\ndouble rho[Ly + 1][Lx + 1], F[Ly + 1][Lx + 1][Q], FEQM[Ly + 1][Lx + 1][Q], U[Ly + 1][Lx + 1][2];
\ndouble F0[Ly + 1][Lx + 1][Q];<\/p>\n

\/\/\u51fd\u6570\u521d\u59cb\u5316
\ndouble feq(int k, double rho, double u[2]);
\nvoid Initialization();
\nvoid Outputdata(int m);<\/p>\n

\/\/\u4e3b\u7a0b\u5e8f
\nint  main()
\n{
\n <\/span>using namespace std;<\/p>\n

<\/span>Initialization();<\/p>\n

<\/span>for (tStep = 1; tStep <= MaxT; tStep++)
\n <\/span>{<\/p>\n

\n <\/span>\/\/1- \u8fc1\u79fb\uff08\u4e0d\u5305\u542b\u8fb9\u754c\uff09
\n <\/span>for (i = 1; i < Lx; i++)
\n <\/span>for (j = 1; j < Ly; j++)
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>{
\n <\/span>{
\n <\/span>ii = i - e[k][0];   jj = j - e[k][1];
\n <\/span>F[j][i][k] = F0[jj][ii][k];
\n <\/span>}
\n <\/span>}
\n <\/span>}<\/p>\n

<\/span>\/\/2- \u8ba1\u7b97\u5b8f\u89c2\u91cf
\n <\/span>for (i = 1; i < Lx; i++)
\n <\/span>for (j = 1; j < Ly; j++)
\n <\/span>{
\n <\/span>{
\n <\/span>rho[j][i] = 0;
\n <\/span>U[j][i][0] = 0;
\n <\/span>U[j][i][1] = 0;
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>rho[j][i] += F[j][i][k];
\n <\/span>U[j][i][0] += e[k][0] * F[j][i][k];
\n <\/span>U[j][i][1] += e[k][1] * F[j][i][k];
\n <\/span>}
\n <\/span>U[j][i][0] \/= rho[j][i];
\n <\/span>U[j][i][1] \/= rho[j][i];
\n <\/span>}
\n <\/span>}<\/p>\n

<\/span>\/\/\u5de6\u53f3\u5b8f\u89c2\u8fb9\u754c
\n <\/span>for (j = 1; j < Ly; j++)
\n <\/span>{
\n <\/span>U[j][0][0] = Uin;   U[j][0][1] = 0;
\n <\/span>U[j][Lx][0] = U[j][Lx - 1][0];   U[j][Lx][1] = 0;
\n <\/span>rho[j][0] = rho[j][1];  rho[j][Lx] = rho0;
\n <\/span>}<\/p>\n

<\/span>\/\/\u4e0a\u4e0b\u58c1\u9762
\n <\/span>for (i = 0; i <= Lx; i++)
\n <\/span>{
\n <\/span>U[0][i][0] = 0;   U[0][i][1] = 0;
\n <\/span>U[Ly][i][0] = 0;   U[Ly][i][1] = 0;
\n <\/span>rho[0][i] = rho[1][i];
\n <\/span>rho[Ly][i] = rho[Ly - 1][i];
\n <\/span>}<\/p>\n

\/\/4- \u78b0\u649e\uff08\u4e0d\u5305\u542b\u8fb9\u754c\uff09
\n <\/span>for (i = 1; i < Lx; i++)
\n <\/span>for (j = 1; j < Ly; j++)
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>{
\n <\/span>{
\n <\/span>F0[j][i][k] = F[j][i][k] - 1 \/ tau*(F[j][i][k] - feq(k, rho[j][i], U[j][i]));
\n <\/span>}
\n <\/span>}
\n <\/span>}<\/p>\n

\n\/\/5- \u5fae\u89c2\u8fb9\u754c\u5904\u7406\uff08\u4e0d\u9700\u8981\u5224\u65ad\u7c7b\u578b\u548c\u65b9\u5411\uff0c\u5904\u7406\u90fd\u4e00\u6837\uff09
\n <\/span>\/\/\u5de6\u53f3\u5fae\u89c2\u8fb9\u754c
\n <\/span>for (j = 1; j < Ly; j++)
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>{
\n <\/span>F0[j][0][k] = feq(k, rho[j][0], U[j][0]) + F0[j][1][k] - feq(k, rho[j][1], U[j][1]);  \/\/\u5165\u53e3
\n <\/span>F0[j][Lx][k] = feq(k, rho[j][Lx], U[j][Lx]) + F0[j][Lx - 1][k] - feq(k, rho[j][Lx - 1], U[j][Lx - 1]); \/\/\u51fa\u53e3
\n <\/span>}
\n <\/span>}
\n <\/span>\/\/\u4e0a\u4e0b\u5fae\u89c2\u8fb9\u754c
\n <\/span>for (i = 1; i < Lx; i++)
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>{
\n <\/span>F0[0][i][k] = feq(k, rho[0][i], U[0][i]) + F0[1][i][k] - feq(k, rho[1][i], U[1][i]);  \/\/\u4e0b\u8fb9\u754c
\n <\/span>F0[Ly][i][k] = feq(k, rho[Ly][i], U[Ly][i]) + F0[Ly - 1][i][k] - feq(k, rho[Ly - 1][i], U[Ly - 1][i]); \/\/\u4e0a\u8fb9\u754c
\n <\/span>}
\n <\/span>}<\/p>\n

\n\/\/6 \u8f93\u51fa\u6570\u636e\u548c\u663e\u793a
\n <\/span>if (tStep % OutN == 0)
\n <\/span>{
\n <\/span>cout << \"\u5165\u53e3\u4e2d\u70b9\u901f\u5ea6\uff1a\" << U[25][1][0] << \"     NO.\" <<tStep<< \"---Steps\" << endl;
\n <\/span>Outputdata(tStep);
\n <\/span>}
\n <\/span>}
\n <\/span>return 0;
\n}
\n\/\/ \u4e3b\u7a0b\u5e8f\u7ed3\u675f~~~~~~~~~~~<\/p>\n

\/\/\u5b50\u7a0b\u5e8f\u4e0e\u51fd\u6570======================================================================
\n\/\/\u5b50\u7a0b\u5e8f1   \u521d\u59cb\u5316\u51fd\u6570
\nvoid Initialization()
\n{
\n <\/span>for (i = 0; i <= Lx; i++)
\n <\/span>for (j = 0; j <= Ly; j++)
\n <\/span>{
\n <\/span>U[j][i][0] = 0; <\/span>U[j][i][1] = 0;
\n <\/span>rho[j][i] = 1;  <\/span>U[j][0][0] = Uin;
\n <\/span>for (k = 0; k < Q; k++)
\n <\/span>{
\n <\/span>F[j][i][k] = feq(k, rho[j][i], U[j][i]);
\n <\/span>F0[j][i][k] = feq(k, rho[j][i], U[j][i]);
\n <\/span>}
\n <\/span>}
\n <\/span>U[0][0][0] = 0;
\n <\/span>U[Ly][0][0] = 0;
\n}<\/p>\n

\n\/\/\/\/\u5b50\u7a0b\u5e8f2   \u8ba1\u7b97\u8f93\u51fa\u901f\u5ea6\u573a\u51fd\u6570
\nvoid Outputdata(int m)
\n{
\n <\/span>ostringstream name;
\n <\/span>name << PathD <\/span><< m << \".dat\";  \/\/\u6570\u636e\u5b58\u50a8\u5730\u5740
\n <\/span>ofstream out(name.str().c_str());
\n <\/span>out << \"Title=\\\"LBM Channel Flow\\\"\\n\"
\n <\/span><< \"VARIABLES=\\\"X\\\",\\\"Y\\\",\\\"U\\\",\\\"V\\\"\\n\"
\n <\/span><< \"ZONE T= \\\"BOX\\\", I= \"
\n <\/span><< Lx + 1 << \", J=\" << Ly + 1 << \", F=POINT\" << endl;
\n <\/span>for (j = 0; j <= Ly; j++)
\n <\/span>for (i = 0; i <= Lx; i++)
\n <\/span>{
\n <\/span>out << double(i) << \" \" << double(j) << \" \"
\n <\/span><< U[j][i][0] << \" \" << U[j][i][1] << endl;
\n <\/span>}
\n}<\/p>\n

\/\/\u51fd\u65701   \u8ba1\u7b97\u5e73\u8861\u6001\u5206\u5e03\u51fd\u6570
\ndouble feq(int k, double rho, double u[2])
\n{
\n <\/span>double eu, uv, feq;
\n <\/span>eu = (e[k][0] * u[0] + e[k][1] * u[1]);
\n <\/span>uv = (u[0] * u[0] + u[1] * u[1]);
\n <\/span>feq = w[k] * rho*(1.0 + 3.0*eu + 4.5*eu*eu - 1.5*uv);
\n <\/span>return feq;
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"

\/\/Program By Yuanqing XU-2022-11-10 #include \"stdafx.h\" … \u7ee7\u7eed\u9605\u8bfb\u201cLBM\u901a\u9053\u6d41 C++\u7248 [2022\u81ea\u7f16]\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[],"views":815,"_links":{"self":[{"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/posts\/1943"}],"collection":[{"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/81.70.49.155\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1943"}],"version-history":[{"count":1,"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions"}],"predecessor-version":[{"id":1944,"href":"http:\/\/81.70.49.155\/index.php?rest_route=\/wp\/v2\/posts\/1943\/revisions\/1944"}],"wp:attachment":[{"href":"http:\/\/81.70.49.155\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1943"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/81.70.49.155\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1943"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/81.70.49.155\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}