MatLab PDE标绘问题

Question

我对Matlab环境非常陌生，我正在Matlab (2014 B)中进行传热模拟。我打算有一个多层墙的不同材料(目前，只有一个单一的材料-铜)，并显示在一个单一的结果在一个地方。一切都很顺利，直到我试图把第三层墙贴在情节上。以下是PDE求解器(R3-R0)基本变量和几何的定义：

k = 400; 
rho = 8960; 
specificHeat = 386; 
thick = .01; 
stefanBoltz = 5.670373e-8; 
hCoeff = 1;
ta = 300;
emiss = .5;

c = thick*k;
a = sprintf('2*%g + 2*%g*%g*u.^3', hCoeff, emiss, stefanBoltz);
f = 2*hCoeff*ta + 2*emiss*stefanBoltz*ta^4;
d = thick*rho*specificHeat;

r0 = [3 4 0 1 1 0 1 1 1.3 1.3];
r1 = [3 4 0 1 1 0 0.6 0.6 1 1];
r2 = [3 4 0 1 1 0 0.3 0.3 0.6 0.6];
r3 = [3 4 0 1 1 0 0 0 0.3 0.3];

下面的代码计算了输入温度为1000 K的壁面底部层(r3)的传热情况：

gdm = r3';
g = decsg(gdm, 'R3', ('R3')');
hmax = .1; % element size
[p, e, t] = initmesh(g, 'Hmax', hmax);    

numberOfPDE = 1;
pb = pde(numberOfPDE);
pg = pdeGeometryFromEdges(g);
uBottom = pdeBoundaryConditions(pg.Edges(1),'u',1000);
pb.BoundaryConditions = uBottom;

u = pdenonlin(pb,p,e,t,c,a,f, 'jacobian', 'lumped');
fprintf('Temperature at the top edge of the plate = %5.1f degrees-K\n', ...
 u(4));

figure
pdeplot(p, e, t, 'xydata', u, 'contour', 'on', 'colormap', 'jet')

hold on

在“稍等”之后，我基本上重复了"r2“矩形的前一段代码，输入温度为"u(4)”(前一层的输出)，然后是最后一段代码：

hold off
axis([0,1,0,2])
caxis manual
caxis([u(4) 1000]);
colorbar; 

就像我说的，这一切都是可行的，第一层和第二层的结果都在同一个地块中。但是，在我重复第三层(r1)的过程，并将结果绘制为原始图(当然，“等待”位位于代码的末尾)之后，该图只显示第三层的结果。我不确定这是Matlab的一些限制，或者我的解决方案是错误的，所以我想寻求一些帮助或一些方向。提前感谢

以下是更好理解的完整代码：

k = 400;
rho = 8960;
specificHeat = 386;
thick = .01;
stefanBoltz = 5.670373e-8;
hCoeff = 1; 
ta = 300;
emiss = .5;

c = thick*k;
a = sprintf('2*%g + 2*%g*%g*u.^3', hCoeff, emiss, stefanBoltz);
f = 2*hCoeff*ta + 2*emiss*stefanBoltz*ta^4;
d = thick*rho*specificHeat;

r0 = [3 4 0 1 1 0 1 1 1.3 1.3];
r1 = [3 4 0 1 1 0 0.6 0.6 1 1];
r2 = [3 4 0 1 1 0 0.3 0.3 0.6 0.6];
r3 = [3 4 0 1 1 0 0 0 0.3 0.3];
%---------------------------------------------------------

gdm = r3';
g = decsg(gdm, 'R3', ('R3')');
hmax = .1; % element size
[p, e, t] = initmesh(g, 'Hmax', hmax);

numberOfPDE = 1;
pb = pde(numberOfPDE);
pg = pdeGeometryFromEdges(g);
uBottom = pdeBoundaryConditions(pg.Edges(1),'u',1000);
pb.BoundaryConditions = uBottom;

u = pdenonlin(pb,p,e,t,c,a,f, 'jacobian', 'lumped');
fprintf('Temperature at the top edge of the plate = %5.1f degrees-K\n', ...
 u(4));

figure
pdeplot(p, e, t, 'xydata', u, 'contour', 'on', 'colormap', 'jet')

hold on

%----------------------------------------------------------------------
gdm = r2';
g = decsg(gdm, 'R2', ('R2')');
hmax = .1; % element size
[p, e, t] = initmesh(g, 'Hmax', hmax);

numberOfPDE = 1;
pb = pde(numberOfPDE);
pg = pdeGeometryFromEdges(g);
uBottom = pdeBoundaryConditions(pg.Edges(1),'u',u(4));
pb.BoundaryConditions = uBottom;

u = pdenonlin(pb,p,e,t,c,a,f, 'jacobian', 'lumped');
fprintf('Temperature at the top edge of the plate = %5.1f degrees-K\n', ...
 u(4));

pdeplot(p, e, t, 'xydata', u, 'contour', 'on', 'colormap', 'jet')

%----------------------------------------------------------------------------
gdm = r1';
g = decsg(gdm, 'R1', ('R1')');
hmax = .1; % element size
[p, e, t] = initmesh(g, 'Hmax', hmax);

numberOfPDE = 1;
pb = pde(numberOfPDE);
pg = pdeGeometryFromEdges(g);
uBottom = pdeBoundaryConditions(pg.Edges(1),'u',u(4));
pb.BoundaryConditions = uBottom;

u = pdenonlin(pb,p,e,t,c,a,f, 'jacobian', 'lumped');
fprintf('Temperature at the top edge of the plate = %5.1f degrees-K\n', ...
 u(4));

pdeplot(p, e, t, 'xydata', u, 'contour', 'on', 'colormap', 'jet')

%----------------------------------------------------------------------------
gdm = r0';
g = decsg(gdm, 'R0', ('R0')');
hmax = .1; % element size
[p, e, t] = initmesh(g, 'Hmax', hmax);

numberOfPDE = 1;
pb = pde(numberOfPDE);
pg = pdeGeometryFromEdges(g);
uBottom = pdeBoundaryConditions(pg.Edges(1),'u',u(4));
pb.BoundaryConditions = uBottom;

u = pdenonlin(pb,p,e,t,c,a,f, 'jacobian', 'lumped');
fprintf('Temperature at the top edge of the plate = %5.1f degrees-K\n', ...
 u(4));

pdeplot(p, e, t, 'xydata', u, 'contour', 'on', 'colormap', 'jet')

%hold off

axis([0,1,0,2])
%caxis manual
caxis([u(4) 1000]);

Answer 1

由于某些原因(我并不完全清楚)，pdeplot函数内部调用hold off。

因此，要获得所需的结果，需要在每次调用hold on之后添加一个pdeplot。