forked from eacdamal/simpar
86 lines
2.2 KiB
C++
86 lines
2.2 KiB
C++
#include <iostream>
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#include <vector>
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#include <math.h>
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#include <iomanip>
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using namespace std;
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int main()
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{
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int l = 1925; // Edge length
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int dx = 40; // Spatial step
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int dt = 100000; // Euler's step
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int kmax = l / dx; // Number of spatial steps
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// Parameters
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double alpha = 0.093;
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double beta = 0.004;
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double gamma = 728.6;
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double h = 0.007;
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// Arrays to store data
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double Q[kmax][dt];
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double P[kmax][dt];
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// Loop over time steps
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for (int i = 0; i < dt; i++)
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{
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// Loop over spatial steps
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for (int k = 0; k < kmax; k++)
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{
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// Boundary condition for the last spatial step
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if (k == kmax - 1)
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{
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Q[k][i] = 0;
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P[k][i] = -202.0; // P = -202 when Q = 10
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} else
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{
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Q[k][i] = 0;
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P[k][i] = 0;
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}
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}
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}
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// Main calculation loop
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for (int i = 2; i < dt; i++)
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{
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// Loop over spatial steps
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for (int k = 1; k < kmax; k++)
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{
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Q[k][i + 1] = Q[k][i] + h * (alpha * (P[k - 1][i] - P[k][i]) - beta * Q[k][i] * abs(Q[k][i]));
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// DO NOT calculate pressure for the last element such as it is given by default
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if (k != kmax - 1)
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P[k][i + 1] = P[k][i - 2] + h * (gamma * (Q[k][i] - Q[k + 1][i]));
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}
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}
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// Print out the first 10 of Q for each spatial step
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std::cout << "FIRST 10 VALUES\n";
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for(int i = 0; i < kmax; i++)
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{
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std::cout.width(5);
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std::cout.flags(std::ios::left);
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std::cout << i << ": ";
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for(int k = 0; k < 10; k++)
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std::cout << std::setw(10) << Q[i][k];
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std::cout << std::endl;
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}
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// Print out the first 10 of Q for each spatial step
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std::cout << "LAST 10 VALUES:\n";
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for(int i = 1; i < kmax; i++)
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{
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std::cout.width(5);
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std::cout.flags(std::ios::left);
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std::cout << i << ": ";
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for(int k = 0; k < 10; k++)
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std::cout << std::setw(10) << Q[i][dt - 10 + k];
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std::cout << std::endl;
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}
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return 0;
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}
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