45 lines
1.1 KiB
Matlab
45 lines
1.1 KiB
Matlab
function [K, F] = CalculateLaplace_mult(model, lambda_wall, lambda_fluid, lambda_air)
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mesh = model.Mesh;
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nodes = mesh.Nodes;
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elements = mesh.Elements;
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Nnodes = size(nodes,2);
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Nelems = size(elements,2);
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K = sparse(Nnodes, Nnodes);
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F = zeros(Nnodes,1);
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% --- build region array manually ---
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regions = zeros(Nelems,1);
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wallElems = findElements(mesh,'region','Face',1);
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fluidElems = findElements(mesh,'region','Face',2);
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airElems = findElements(mesh,'region','Face',3);
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regions(wallElems) = 1;
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regions(fluidElems) = 2;
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regions(airElems) = 3;
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for e = 1:Nelems
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vert = elements(:,e);
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x = nodes(1,vert);
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y = nodes(2,vert);
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Ae = polyarea(x,y);
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b = [y(2)-y(3); y(3)-y(1); y(1)-y(2)];
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c = [x(3)-x(2); x(1)-x(3); x(2)-x(1)];
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% conductivity by material
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switch regions(e)
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case 1
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lambda = lambda_wall;
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case 2
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lambda = lambda_fluid;
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case 3
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lambda = lambda_air;
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otherwise
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error('Element %d has no material assignment', e);
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end
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Ke = (lambda/(4*Ae)) * (b*b.' + c*c.');
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K(vert,vert) = K(vert,vert) + Ke;
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end
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end
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