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tAdded Courant criteria for ensuring numerical stability - lbm-d3q19 - 3D latti… |
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git clone git://src.adamsgaard.dk/lbm-d3q19 |
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--- |
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commit 1e0a6e6406bfb66a9c64fb94e8370ea2513ecea7 |
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parent 432185412169f2d169eaec398cfa9154642e4bd2 |
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Author: Anders Damsgaard <[email protected]> |
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Date: Tue, 25 Jun 2013 12:33:55 +0200 |
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Added Courant criteria for ensuring numerical stability |
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Diffstat: |
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M lbm.c | 16 +++++++++++++++- |
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1 file changed, 15 insertions(+), 1 deletion(-) |
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--- |
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diff --git a/lbm.c b/lbm.c |
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t@@ -3,7 +3,6 @@ |
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#include <math.h> |
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// Courant kriterie for tidsskridt |
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-// Check for LBM stability criteria |
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// No slip top og bund |
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// Periodiske sider |
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t@@ -64,6 +63,9 @@ const Float rho0 = 1.0; |
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// Inital cell fluid velocity (dimensionless) |
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const Float3 u0 = {0.0, 0.0, 0.0}; |
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+// Courant criteria limit |
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+const Float C_max = 1.0; |
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+ |
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//// FUNCTION DEFINITIONS |
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t@@ -254,6 +256,18 @@ Float3 find_u( |
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u.y += f_i*e[i].y/rho; |
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u.z += f_i*e[i].z/rho; |
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} |
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+ |
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+ // Check the Courant-Frederichs-Lewy condition |
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+ if ((u.x*dt/dx + u.y*dt/dx + u.z*dt/dx) > C_max) { |
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+ fprintf(stderr, "Error, the Courant-Friderichs-Lewy condition is not "… |
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+ fprintf(stderr, "satisfied.\nTry one or more of the following:\n"); |
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+ fprintf(stderr, "- Decrease the timestep (dt)\n"); |
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+ fprintf(stderr, "- Increase the cell size (dx)\n"); |
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+ fprintf(stderr, "- Decrease the fluid viscosity (nu)\n"); |
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+ fprintf(stderr, "- Decrease the fluid density (rho)\n"); |
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+ exit(EXIT_FAILURE); |
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+ } |
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+ |
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return u; |
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} |
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