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# [Nastran] Reduced Frequency

## [Nastran] Reduced Frequency

(OP)
According to the Nastran manual, to analyze the flutter with the pk method, the reduced frequency must be entered with the mkaero command. When entering mkaero, I know that it can be obtained by entering the mode frequency from sol103 and v_min and v_max.

1. If you look at .f06 analyzed by the solver, you will also find a reduced frequency called KFREQ or 1/KFREQ. Both are reduced frequencies, what is the difference between mkaero and KFREQ?

I understood that the reduced frequency provided by mkaero is provided to create a modal aerodynamic damping/stiffness matrix in the fundamental equation.

2. What is the purpose of KFREQ to analyze? flutter results using only damping, velocity, and frequency when drawing vg and vf graphs.
[Source: 2021.help.altair.com/]

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