1 | %The aim of this program is to compare a model with an analytical solution given in MacAyeal EISMINT : Lessons in Ice-Sheet Modeling
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2 | printingflag=false;
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3 |
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4 | numlayers=10;
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5 | resolution=30000;
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6 |
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7 | %To begin with the numerical model
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8 | md=model();
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9 | md=roundmesh(md,750000,resolution);
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10 | md=setmask(md,'',''); %We can not test iceshelves nor ice rises with this analytical solution
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11 | md=parameterize(md,'../Par/RoundSheetStaticEISMINT.par');
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12 |
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13 | %Calculation of the analytical 2d velocity field
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14 | constant=0.3;
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15 | vx_obs=constant/2*md.mesh.x.*(md.geometry.thickness).^-1;
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16 | vy_obs=constant/2*md.mesh.y.*(md.geometry.thickness).^-1;
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17 | vel_obs=(sqrt((md.inversion.vx_obs).^2+(md.inversion.vy_obs).^2));
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18 |
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19 | %We extrude the model to have a 3d model
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20 | md=extrude(md,numlayers,1);
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21 | md=setflowequation(md,'stokes','all');
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22 |
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23 | %Spc the nodes on the bed
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24 | pos=find(md.mesh.vertexonbed);
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25 | md.diagnostic.spcvx(pos)=0;
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26 | md.diagnostic.spcvy(pos)=0;
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27 | md.diagnostic.spcvz(pos)=0;
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28 |
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29 | %Now we can solve the problem
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30 | md.cluster=generic('name',oshostname(),'np',8);
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31 | md=solve(md,DiagnosticSolutionEnum());
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32 |
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33 | %Calculate the depth averaged velocity field (2d):
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34 | vx=(md.results.DiagnosticSolution.Vx);
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35 | vy=(md.results.DiagnosticSolution.Vy);
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36 | vel=zeros(md.mesh.numberofvertices2d,1);
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37 |
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38 | node_vel=0;
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39 | for i=1:md.mesh.numberofvertices2d
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40 | for j=1:(md.mesh.numberoflayers-1)
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41 | node_vel=node_vel+1/(2*(md.mesh.numberoflayers-1))*(sqrt(vx(i+j*md.mesh.numberofvertices2d,1).^2+...
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42 | vy(i+j*md.mesh.numberofvertices2d,1).^2)+...
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43 | sqrt(vx(i+(j-1)*md.mesh.numberofvertices2d,1).^2+vy(i+(j-1)*md.mesh.numberofvertices2d,1).^2));
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44 | end
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45 | vel(i,1)=node_vel;
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46 | node_vel=0;
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47 | end
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48 |
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49 | %Plot of the velocity from the exact and calculated solutions
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50 | figure(1)
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51 | subplot(2,2,1)
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52 | p=patch('Faces',md.mesh.elements2d,'Vertices',[md.mesh.x2d md.mesh.y2d],'FaceVertexCData',...
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53 | vel,'FaceColor','interp','EdgeColor','none');
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54 | title('Modelled velocity','FontSize',14,'FontWeight','bold')
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55 | colorbar;
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56 | caxis([0 200]);
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57 |
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58 | subplot(2,2,2)
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59 | p=patch('Faces',md.mesh.elements2d,'Vertices',[md.mesh.x2d md.mesh.y2d],'FaceVertexCData',...
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60 | vel_obs,'FaceColor','interp','EdgeColor','none');
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61 | title('Analytical velocity','FontSize',14,'FontWeight','bold')
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62 | colorbar;
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63 | caxis([0 200]);
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64 |
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65 | subplot(2,2,3)
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66 | hold on;
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67 | plot(sqrt((md.mesh.x(1:md.mesh.numberofvertices2d)).^2+(md.mesh.y(1:md.mesh.numberofvertices2d)).^2),vel,'r.');
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68 | plot(sqrt((md.mesh.x2d).^2+(md.mesh.y2d).^2),vel_obs,'b.');
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69 | title('Analytical vs calculated velocity','FontSize',14,'FontWeight','bold');
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70 | xlabel('distance to the center of the icesheet [m]','FontSize',14,'FontWeight','bold');
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71 | ylabel('velocity [m/yr]','FontSize',14,'FontWeight','bold');
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72 | legend('calculated velocity','exact velocity');
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73 | axis([0 750000 0 200]);
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74 | hold off;
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75 |
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76 | subplot(2,2,4)
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77 | p=patch('Faces',md.mesh.elements2d,'Vertices',[md.mesh.x2d md.mesh.y2d],'FaceVertexCData',...
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78 | abs(vel-vel_obs)./vel_obs*100,'FaceColor','interp','EdgeColor','none');
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79 | title('Relative misfit [%]','FontSize',14,'FontWeight','bold')
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80 | colorbar;
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81 | caxis([0 100]);
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82 |
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83 | if printingflag,
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84 | set(gcf,'Color','w')
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85 | printmodel('stokesstatic','png','margin','on','marginsize',25,'frame','off','resolution',0.7,'hardcopy','off');
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86 | system(['mv stokesstatic.png ' ISSM_DIR '/website/doc_pdf/validation/Images/EISMINT/IceSheet']);
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87 | end
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88 |
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89 | %Fields and tolerances to track changes
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90 | field_names ={ ...
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91 | 'Vx','Vy','Vel', ...
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92 | };
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93 | field_tolerances={...
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94 | 1e-12,1e-12,1e-12, ...
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95 | };
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96 | field_values={
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97 | vx,vy,vel, ...
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98 | };
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