3D PDE modelling different c coefficients for different spatial regions

1 次查看(过去 30 天)
Hi,
I have a geometry imported into MATLAB shown in the picture below.
For reference, the cube describes tissue bed and the cylindrical holes describe blood vessel with dirichlet pressure boundary conditions.
I am trying to specify c coefficients to change the properties in a spherical region within the cube,
with the coefficient inside and outside this spherical region set to different scalar values.
I know you cannot specify subdomains in the same way as in the 2D pde modeller, but I tried to use an "if statement" to spatially set c coefficients without much luck.
function c = c_region_3D(location,state)
%% Input variables for region which we want to alter
% sphere 1
xc_old1=0.1875;
yc_old1=0.1875;
zc_old1= 0.125;
r_old=0.1;
a=1; % counter for all voxels within cube
for i=1:length(location.x)
for j=1:length(location.y)
for k=1:length(location.z)
if ((location.x(i)-xc_old1).^2 + (location.y(j)-yc_old1).^2 + (location.z(k)-zc_old1).^2<=(r_old).^2)==1
c(1,a) = 3.3929e-13;
a=a+1;
else
c(1,a) = 4.4762e-13;
a=a+1;
end
end
end
end
However, I only seem to be able to provide a c matrix with the length of one side of the cube - how do I therefore reference 3D points to specify the c coefficient in this region?
Thank you!

采纳的回答

Ravi Kumar
Ravi Kumar 2020-4-7
Hi Barnaby,
If all you want is different values of c for points within sphere and outside sphere, then you can just do this:
function c = c_region_3D(location,state)
xc_old1=0.1875;
yc_old1=0.1875;
zc_old1= 0.125;
r_old=0.1;
c = zeros(size(location.x));
%find IDs of points in sphere or not and use it for logical indexing.
Index_of_PointsInSphere = (location.x-xc_old1).^2 + (location.y-yc_old1).^2 + (location.z-zc_old1).^2<=(r_old).^2;
Index_of_Points_NOT_InSphere = ~Index_of_PointsInSphere;
c(Index_of_PointsInSphere) = 3.3929e-13;
c(Index_of_Points_NOT_InSphere) = 4.4762e-13;
end
Regards,
Ravi

更多回答(0 个)

类别

Help CenterFile Exchange 中查找有关 Geometry and Mesh 的更多信息

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by