transonic-similaritylisted
Install: claude install-skill ashfordeOU/aero-agent-skills
# Transonic Similarity Corrections (aerodynamics/high-speed/transonic-similarity)
Use when the task is compressibility corrections for high-subsonic
flows: the Prandtl-Glauert and Karman-Tsien pressure coefficient
corrections, the transonic similarity parameter, and critical Mach
estimation.
## Domain quick reference
- Prandtl-Glauert (linearized thin-airfoil theory, valid below
M ~ 0.7): perturbation quantities scale with the factor
1 / sqrt(1 - M^2). Pressure coefficient C_p = C_p0 / sqrt(1 - M^2),
lift coefficient C_L = C_L0 / sqrt(1 - M^2), and section lift-curve
slope a = a0 / sqrt(1 - M^2), where subscript 0 marks the
incompressible value.
- Karman-Tsien (extended, usable toward M ~ 0.85):
C_p = C_p0 / (sqrt(1 - M^2) + (M^2 / (1 + sqrt(1 - M^2))) * C_p0 / 2).
The denominator shrinks less than the Prandtl-Glauert factor alone,
so the correction stays finite closer to M = 1.
- Transonic similarity parameter: K = (1 - M^2) / tau^(2/3), with tau
the thickness ratio (sweep enters through the effective Mach
M * cos(Lambda)). Two thin configurations with equal K have similar
pressure fields near M = 1.
- Critical pressure coefficient (isentropic sonic limit at freestream
Mach M, gamma = 1.4 default):
C_p* = (2 / (gamma * M^2)) * (((1 + (gamma - 1) / 2 * M^2) /
(1 + (gamma - 1) / 2))^(gamma / (gamma - 1)) - 1). Local flow is
sonic where C_p equals C_p*.
- Critical Mach number M_cr: solve C_p0 / sqrt(1 - M^2) = C_p*(M) for
the smallest M; the p