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Basic Usage

The solve() Function

The main entry point is solve(), which examines the parameters you provide and dispatches to the appropriate calculation.

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from flow_state import solve

Input Modes

Mode Parameters Use Case
Stagnation mach, pres_stag, temp_stag Wind tunnels
Flight mach, altitude, atm Trajectory points
Static mach, pres, temp Direct specification
Reynolds mach, re1, temp Matching Re conditions

See Examples for concrete usage of each mode.

Unit Support

Dimensional inputs accept (value, "unit") tuples:

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state = solve(mach=6, pres_stag=(140, "psi"), temp_stag=420)
state = solve(mach=7, altitude=(100000, "ft"), atm="ussa76")
Quantity Units
Pressure Pa, psi, atm, bar, torr
Temperature K, C, F, R
Length m, ft, km, mi

The FlowState Object

solve() returns a FlowState, a frozen dataclass with all computed properties:

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state = solve(mach=6.0, pres_stag=(140, "psi"), temp_stag=420)

state.mach       # Mach number
state.pres       # Static pressure [Pa]
state.temp       # Static temperature [K]
state.dens       # Density [kg/m³]
state.uvel       # Velocity [m/s]
state.re1        # Unit Reynolds number [1/m]
state.pres_stag  # Stagnation pressure [Pa]
state.temp_stag  # Stagnation temperature [K]

Print a formatted summary:

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print(state)

See API Reference for the complete list of properties.

Gas and Transport Models

By default, solve() uses air with Sutherland viscosity. Use the gas parameter for other gases:

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state = solve(mach=10, pres_stag=(1800, "psi"), temp_stag=1000, gas="n2")

See Theory → Gas Models for available models and temperature ranges.