Mason Shopperly — NotesShort pieces on CFD, numerics, and machine work — what's loaded on the working surface right now.https://masonshopperly.com/Working through the Zingg two-book archttps://masonshopperly.com/notes/numerics-zingg-two-book-arc/https://masonshopperly.com/notes/numerics-zingg-two-book-arc/The two-book numerics arc — analytical foundations, then shock-capturing — rebuilt on my own time. CFDLab is the artefact that came out the other side.Tue, 28 Apr 2026 00:00:00 GMTBMW E70 X5d — drivetrain rumble, suspect the guibohttps://masonshopperly.com/notes/bmw-e70-x5d-guibo-diagnosis/https://masonshopperly.com/notes/bmw-e70-x5d-guibo-diagnosis/Diesel X5 with a low-rpm rumble that builds with load. First suspect is the driveshaft flex disc — the guibo. Diagnosis pass before any parts go on.Tue, 28 Apr 2026 00:00:00 GMTBMW X1 28i (2017) — coils + plugs resethttps://masonshopperly.com/notes/bmw-x1-28i-coils-plugs/https://masonshopperly.com/notes/bmw-x1-28i-coils-plugs/Full ignition baseline reset on a 2017 X1 28i — coils and plugs replaced as a single pass so any subsequent misfire diagnosis starts from a known-good state.Tue, 28 Apr 2026 00:00:00 GMTYamaha Enticer 250 — bogey wheel sitting on the track edgehttps://masonshopperly.com/notes/yamaha-enticer-250-repairs/https://masonshopperly.com/notes/yamaha-enticer-250-repairs/Belt replaced and ski repair done. The remaining thread is the bogey wheel that's been riding the inside edge of the track — a geometry problem, not a parts problem.Tue, 28 Apr 2026 00:00:00 GMTGaggiuino — PID and profiling on a Gaggia Classic Prohttps://masonshopperly.com/notes/gaggiuino-classic-pro-build/https://masonshopperly.com/notes/gaggiuino-classic-pro-build/Open the Classic Pro, replace its internals with an open-source PID + pressure-profiling controller, close it back up. Started for the value-per-dollar; staying for the repeatability.Sun, 26 Apr 2026 00:00:00 GMTAhmed body — y⁺ pass on the baseline gridhttps://masonshopperly.com/notes/ahmed-y-plus-pass/https://masonshopperly.com/notes/ahmed-y-plus-pass/Wall-resolved versus wall-modelled. What the residual histogram says about the inflation layer on the M25 baseline.Sat, 25 Apr 2026 00:00:00 GMTWhat SBP operators are actually doing at a boundaryhttps://masonshopperly.com/notes/sbp-boundary-closures/https://masonshopperly.com/notes/sbp-boundary-closures/A field engineer's read of summation-by-parts: where the dual norm earns its name, and where it doesn't.Wed, 22 Apr 2026 00:00:00 GMTBMW E89 Z4 — maintenance loghttps://masonshopperly.com/notes/bmw-e89-z4-maintenance/https://masonshopperly.com/notes/bmw-e89-z4-maintenance/Oil filter housing gasket, ignition coils and plugs, catalyst downpipes, upgraded charge pipe, factory diverter removed for a TiAL BOV. Done in the driveway.Mon, 20 Apr 2026 00:00:00 GMT