OpenMDAO
Aviary internal atmosphere model with humidity and temperature delta options
Summary
Adds atmos_1976.py to /subsystems/atmosphere, which is obtained from dymos. The model has been modified to include options to output absolute humidity and correct the atmosphere for temperature delta from ISA standard day conditions. A temperature correction has been applied to the computed values, since the tables assume a fixed temperature for a given altitude.
The current setup does not account for attenuation of the temperature delta with increasing altitude (which ends at the tropopause), so this option must be toggled manually by the user to accurately represent real atmosphere conditions.
Please check my math for the temperature corrections if possible. I have run some independent testing and seen good lineup, but I have not fully verified the derivative calculations. I am also seeing a slight deviation in the temperature-corrected viscosity compared to 1976 atmosphere table calculators, which I believe to be due to loss of significant digits from Sutherland's constant for air. I don't expect this to impact anything in Aviary, but it might be able to be improved.
Related Issues
None
Backwards incompatibilities
None
New Dependencies
None
I spoke to Jess about adding a small test to this, just to verify a couple of value against a db somewhere so that we don't break it.
Closing this for now. A new PR that combines this with the MIL-STD atmosphere is being prepared by Eliot and Jess.