pdeplot3d "value of 'colormapdata' is invalid" or "Length of colormapdata vector must equal number of nodes."

Hello,

I am a new user to the pde toolbox. The script I am using is at the bottom of thiis question. If I run the code as it stands, I get the output:

thermalresults =

TransientThermalResults with properties:

Temperature: [8654×11 double]

SolutionTimes: [0 0.5000 1 1.5000 2 2.5000 3 3.5000 4 4.5000 5]

XGradients: [8654×11 double]

YGradients: [8654×11 double]

ZGradients: [8654×11 double]

Mesh: [1×1 FEMesh]

Error using pdeplot3D

Length of colormapdata vector must equal number of nodes.

Error in heatTransfer_v2 (line 33)

pdeplot3D(thermalmodel,"ColorMapData",thermalresults.Temperature(:,end), ...

====================================================================

whereas if I uncomment the alternative pdeplot3D command (commented out below), I get:

========================================================

thermalresults =

TransientThermalResults with properties:

Temperature: [8654×11 double]

SolutionTimes: [0 0.5000 1 1.5000 2 2.5000 3 3.5000 4 4.5000 5]

XGradients: [8654×11 double]

YGradients: [8654×11 double]

ZGradients: [8654×11 double]

Mesh: [1×1 FEMesh]

Error using pdeplot3D

The value of 'colormapdata' is invalid. Operands to the logical AND (&&) and OR (||) operators must

be convertible to logical scalar values. Use the ANY or ALL functions to reduce operands to logical

scalar values.

Error in heatTransfer_v2 (line 29)

pdeplot3D(thermalmodel,"ColorMapData",thermalresults.Temperature, ...

================================================================================

I have looked through the various examples in the pdetoolbox such as here:

Heat Conduction in Multidomain Geometry with Nonuniform Heat Flux - MATLAB & Simulink - MathWorks United Kingdom

but so far I can't see what I need to do.

Thanks in advance

Chris

======================================================================

thermalmodel = createpde('thermal','transient');

pg = importGeometry(thermalmodel,'cylinder3.stl');

pdegplot(thermalmodel,'FaceLabels','on')

ylim([-1,1])

axis equal

thermalProperties(thermalmodel,'ThermalConductivity',1,...

'MassDensity',1,...

'SpecificHeat',1);

thermalBC(thermalmodel,'Face',1,'Temperature',100);

thermalBC(thermalmodel,'Face',5,'HeatFlux',10);

thermalIC(thermalmodel,0);

generateMesh(thermalmodel);

figure

pdemesh(thermalmodel)

title('Mesh with Quadratic Triangular Elements')

tlist = 0:0.5:5;

thermalresults = solve(thermalmodel,tlist)

[qx,qy] = evaluateHeatFlux(thermalresults);

%pdeplot3D(thermalmodel,"ColorMapData",thermalresults.Temperature, ...

% 'FlowData',[qx,qy], ...

% 'ColorMap','hot')

pdeplot3D(thermalmodel,"ColorMapData",thermalresults.Temperature(:,end), ...

'FlowData',[qx(:,end),qy(:,end)], ...

'ColorMap','hot')

Answer 1

[Chris]

I'm not familiar with this toolbox, but...

• You have a 3D model, but only 2D flux.

[qx,qy,qz] = evaluateHeatFlux(thermalresults);

• It doesn't look to me like 'ColorMap' is a valid argument for pdeplot3d.

pdeplot3D(thermalmodel,'FlowData',[qx(:,end),qy(:,end),qz(:,end)],...
    'ColorMapData',thermalresults.Temperature(:,end))
colormap hot

[Christopher]

Thankyou, I find eliminating the FlowData helps, so that the command:

pdeplot3D(thermalmodel,"ColorMapData",thermalresults.Temperature(:,end))

works for me.