TPG EOS update for multiple cp polynomials #634
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New format allows for temperature ranges to be defined in variable t_range, which expects 4 temperatures (to define 3 ranges). All chemical species which I expect to be included in our study require this many ranges. The cp_coeff structure is updated to be a nested vector, to contain 3 sets of polynomials coefficients per species. Regression test lua file is updated with the new format.
Enthalpy polynomials are given with respect to a reference temp (T_ref = 298.15 K), and the added reference enthalpy shifts this to be (T_ref = 0 K). This fixes the problem of negative internal energies encountered for a simple 1D normal shock problem.
Single species, but the temperature post shock is large enough to require TPG description (and 2 polynomials from NASA Glenn). Test setup from https://doi.org/10.1002/fld.5079
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The NASA Glenn polynomials span specific temperature ranges, and there are multiple polynomials per coefficient to describe a complete temperature range from [200 K -- 20000 K]. Updated the input deck structure to accommodate multiple cp polynomials, each with a defined temperature range.
Additionally, the NASA Glenn polynomials elect to have h(T_ref = 298.15 K) = 0. Not accounting for this will give negative internal energies for realistic problems. A new input, dH_ref, shifts the reference enthalpy temperature to be T = 0 K.
A new regression test is added to check the results of pure N2 gas across a Mach 8 shock wave, which results in a post-shock temperature well into the TPG regime.
This change is