Sending the smoke down 1 m cost 7 Pa of draft — Franklin's stove and the buoyancy budget
·8 min read
One metre of down-leg removes 6.16 Pa and the longer chimney gives back less, 38.32 Pa instead of 39.15. Net draft falls from 44.72 Pa to 37.72 Pa.
Chaos That Begins at the Bottom of a Pot — Rayleigh–Bénard Convection and the Lorenz Equations
·5 min read
Rolls switch on at Rayleigh number 1708 with rigid walls. In the Lorenz truncation that heating, written as rho, stops settling once rho passes 24.74.
Fluid That Warms Up While Standing Still — Natural Convection and Rayleigh 1708
·6 min read
A 0.30 m wall at 60 C in 20 C air prints Ra 7.03e7, Nu 54.9, and a heat flux of 197.6 W/m^2, still on the laminar side of 1e9.
[Paper Review] When 30 K Breaks Boussinesq — Demou (2018) NOB Natural Convection and the Pressure Split
·5 min read
For water at ΔT=30 K the printed split correction max |1-rho0/rho| is 0.0117, while the pressure Poisson stays constant-coefficient.