The Shah 1982 CHART correlation for saturated boiling heat transfer as SysML Activity Diagrams (2): Detailed view of the hex$SI$Shah$twophase$htc$combined SI Real convention function variant
SysML Activity Diagrams can be very useful for analysing complex networks of equations and for optimising and organising Wolfram Language code.
This example is relatively simple!
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For reference, some associated Policy Notes (you don't need to visit these links yet):