Transient stress analysis for vertical channels

[hf360F]

There are some other changes besides the additions to the Engine.run_stress_analysis() method:

• Blockage ratio for vertical channels (the fraction of the coolant channel cross-sectional area taken up by the ribs / cage, currently does not impact heat transfer),
• Requirement for the outer liner to be specified for CoolingJacket objects (relevant examples have been updated to work)
• Support for variable outer liner thickness, as with inner liner thickness
• Temp / yield data for 304 steel
• Rewritten stress_example.py to be clearer - the old way of presenting the result with a colourmap is no longer sufficient at presenting all of the relevant data

[dug20]

Looks awesome, will update the docs soon.

Might be worth making outer liner a kwarg, so you can run heating simulations without it, but then have it raise an error if you try to run a stress simulation and it's unspecified. Although not a big issue so might not be worth it if it's troublesome.

[hf360F]

That was originally how I had it, I've now changed it back