Isentropic Flow Calculator
Type into any box — Mach number, a stagnation ratio, the area ratio — and everything else follows, on both sides of the throat at once. At any γ.
| Quantity | Subsonic before the throat | Supersonic after the throat |
|---|
Ratios against Mach number
p/p₀
T/T₀
ρ/ρ₀
sonic point
What this is computing
NOT WRITTEN YET — Iliya writes this, 300–500 words.
Deliberately loud so it cannot ship by accident. Worth covering:
- What "isentropic" is actually assuming, and when a real nozzle stops obeying it — shocks, separation, heat transfer, friction.
- Why A/A* has two roots and what physically picks between them: the back pressure, not the geometry. This is the conceptual trap on this page, the same shape as weak-versus-strong on the oblique page.
- Why A/A* ≥ 1 always, and what it means that the throat is where A/A* = 1.
- The sonic reference ratios, and why tables are often printed against them rather than against stagnation conditions.
- Why γ matters here: nozzle area ratio for a given exit Mach number changes materially between air at 1.4 and combustion products near 1.2, which is exactly the case a rocket person has.