Something like this may suffice. It probably needs quite a bit of tweaking (labels, titles, geometry adjustment) still, but it's a start.
maxradius = 0.0008;
x = linspace(0,maxradius,10);
t = linspace(0,200,50);
m = 0;
eqn = @(x,t,u,dudx) fluidPDE(x,t,u,dudx);
ic = @(x) fluidIC(x);
bc = @(xl,ul,xr,ur,t) fluidBC(xl,ul,xr,ur,t);
sol = pdepe(m,eqn,ic,bc,x,t);
u = sol(:,:,1);
figure(1)
surf(x,t,u)
title('Moisture content')
xlabel('Radius [m]')
ylabel('Time [s]')
zlabel('Moisture content [-]')
figure(2)
hold on
plot(x,u(5,:),'Linewidth',2)
plot(x,u(20,:),'Linewidth',2)
plot(x,u(30,:),'Linewidth',2)
plot(x,u(40,:),'Linewidth',2)
plot(x,u(end,:),'Linewidth',2)
legend('t=5 s','t=20 s','t=30 s','t=40 s','t=50 s')
xlabel('Radius [m]')
ylabel('Moisture content [-]')
title('Moisture content')
% this is the new part
figure(3)
nth = 100;
th = linspace(0,2*pi,nth).';
xx = x.*cos(th);
yy = x.*sin(th);
timeindices = [5 20 30 40];
datarange = [min(u(timeindices,:),[],'all') max(u(timeindices,:),[],'all')];
px = ceil(sqrt(numel(timeindices)));
py = numel(timeindices)/px;
pidx = reshape(1:py*(px+1),px+1,py).';
for k = 1:numel(timeindices)
subplot(py,px+1,pidx(k))
pcolor(xx,yy,repmat(u(timeindices(k),:),[nth 1]));
shading flat
caxis(datarange)
colormap(jet)
axis equal off
ht = text(-1.2*maxradius,-1.2*maxradius, ...
sprintf('time = %d sec',timeindices(k)));
end
ha = subplot(py,px+1,pidx(k+(1:2)));
hp = get(ha,'Position');
caxis(datarange)
colorbar('Position', hp.*[1 1 0.5 0.75] + [hp(3)*0.25 hp(4)*0.125 0 0])
axis off
function [c,f,s] = fluidPDE(x,t,u,dudx) % Equation to solve
D=3e-9;
c = 1/D;
f = dudx;
s = 2/x;
end
% ----------------------------------------------------
function u0 = fluidIC(x) % Initial condition
X0=0.2;
u0 = X0;
end
% ----------------------------------------------------
function [pl,ql,pr,qr] = fluidBC(xl,ul,xr,ur,t) % Boundary conditions
D=3e-9;
rop=2500;
k=1.8e-4;
uf=0.05;
pl = 0;
ql = 1;
pr = k*(ur-uf);
qr = D;
end
