Screen simulation

solids -> oversize + undersize (PSD cut)

Governing equations

The exact equations the solver works for a screen — the same math shown in the app's "Theory" panel, not a black box.

F_{under}=\Phi\!\Big(\frac{\ln(c/d_{50})}{\ln\sigma_g}\Big)\;\;(\text{log-normal PSD partition at cut } c)

cut_size_m [m, required]; the feed PSD (mean_size_m, gsd) rides on the solid stream's solids payload from upstream