The Kinked String Was Fine, the Cut String Overshot by 9% — How the 1747 Wave-Equation Fight Ended Numerically
·5 min read
d'Alembert's travelling waves and Bernoulli's sine series are the same solution, until you truncate. Code shows where the 9% overshoot comes from and why smoothness decides.
The Outlet Is Open, Yet the Wave Comes Back — NSCBC and the Price of σ
·8 min read
At a non-reflecting outlet, one coefficient sets both reflection and pressure drift
[Paper Review] A Droplet Sends Almost Every Sound Wave Back — Acoustic Impedance and a Sharp-Interface Two-Phase Solver
·8 min read
Why a liquid-gas interface reflects 99.9% of an acoustic wave, and the fake sound speed a smeared interface invents
Supersonic Flow Can't See Upstream — Characteristics and Sound Waves in the Euler Equations
·5 min read
Why a small disturbance splits into three characteristic speeds