The Coriolis Force Did Zero Work, Yet the Impeller Added 1800 J/kg — Energy in a Rotating Frame
·7 min read
What a rotating frame conserves is rothalpy, not total enthalpy. Here is why the Coriolis force never does work on the fluid, and where a pump's head actually comes from, checked numerically.
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.
Sending the smoke down 1 m cost 7 Pa of draft — Franklin's stove and the buoyancy budget
·7 min read
The chimney top never moves, yet one descending leg breaks the draft. We write out the buoyancy ledger, then find the fire temperature at which smoke spills into the room.
1950 — When von Neumann Deliberately Smeared the Shock: Artificial Viscosity and Odd-Even Decoupling
·5 min read
The ξ²(Δu)² trick that killed post-shock wiggles, and the new problem it left behind.