{ "name": "SpectraSim 0.6.0a1 verification and validation results", "source": "https://spectrasimulations.com/validation/", "release": "0.6.0a1", "runs": "verification runs of 2026-10 and 2026-11", "acceptance": "Acceptance criterion for acoustics against measurement: within ±3 dB over the frequency range of the measurement; flow results are compared case by case as stated.", "lastUpdated": "2026-11-02", "referenceTypes": { "measured": "Measured", "analytical": "Analytical", "code-to-code": "Code-to-code", "symmetry": "Symmetry", "self": "Self-consistency", "other": "Other reference" }, "rows": [ { "id": "tl-extended-tube", "area": "acoustics", "case": "Muffler with an extended-tube chamber, 20 °C, 20–1000 Hz", "referenceType": "code-to-code", "referenceTypeLabel": "Code-to-code", "reference": "the same model in a commercial finite-element code", "result": "transmission loss rms 0.12 dB, largest 1.3 dB; the 815 Hz notch at the same frequency", "url": "https://spectrasimulations.com/validation/#tl-extended-tube" }, { "id": "tl-two-inlet", "area": "acoustics", "case": "Two-inlet muffler with eight internal walls, 450 °C, 20–500 Hz", "referenceType": "code-to-code", "referenceTypeLabel": "Code-to-code", "reference": "commercial finite-element code", "result": "median 0.9 dB, rms 3.2 dB; the sharp notches (65 dB) carry the largest differences; the reference mesh's convergence is not known", "url": "https://spectrasimulations.com/validation/#tl-two-inlet" }, { "id": "tl-absorbing-three-region", "area": "acoustics", "case": "Large exhaust muffler with three absorbing-material regions, 20–500 Hz", "referenceType": "code-to-code", "referenceTypeLabel": "Code-to-code", "reference": "commercial finite-element code, its finest mesh", "result": "rms 0.16 dB, median 0.04 dB, largest 0.49 dB", "url": "https://spectrasimulations.com/validation/#tl-absorbing-three-region" }, { "id": "tl-sullivan-crocker", "area": "acoustics", "case": "Concentric-tube resonators (Sullivan and Crocker, 1978)", "referenceType": "measured", "referenceTypeLabel": "Measured", "reference": "measured transmission loss", "result": "main peak 7–10 % lower in frequency than measured, peak levels within about 2 dB; humps within 1 dB", "url": "https://spectrasimulations.com/validation/#tl-sullivan-crocker" }, { "id": "tl-splitter-measured", "area": "acoustics", "case": "Parallel-baffle (splitter) silencer, mineral fibre with a porous foil cover, 50–4000 Hz", "referenceType": "measured", "referenceTypeLabel": "Measured", "reference": "measured transmission loss (Mechel, Formulas of Acoustics, 2008, J.22)", "result": "rms 1.37 dB, largest 2.94 dB; all bands from 100 Hz to 4 kHz within ±3 dB; the 630 Hz peak reproduced", "url": "https://spectrasimulations.com/validation/#tl-splitter-measured" }, { "id": "tl-pod-silencer", "area": "acoustics", "case": "Pod silencer with absorbing pod and lining (Munjal, 2003), 20–5000 Hz", "referenceType": "analytical", "referenceTypeLabel": "Analytical", "reference": "the paper's bulk-reacting plane-wave theory, solved again with the same inputs", "result": "absorbing section rms 1.3 dB, largest 2.3 dB below the 1.7 kHz cut-on; the paper's printed curve is matched below 1 kHz (rms 2.9 dB) and lies 7–13 dB lower above it, most likely an unreported protective perforate", "url": "https://spectrasimulations.com/validation/#tl-pod-silencer" }, { "id": "tl-double-plug", "area": "acoustics", "case": "Double-plug muffler with mean flow, 0.0556 kg/s", "referenceType": "other", "referenceTypeLabel": "Other reference", "reference": "reference curve supplied with the model (source not yet identified)", "result": "rms 2.5–3.0 dB depending on the perforate model; about +3 dB at 300–900 Hz, most likely the missing mean-flow convection in the duct", "url": "https://spectrasimulations.com/validation/#tl-double-plug" }, { "id": "exact-1d", "area": "acoustics", "case": "Straight duct, expansion chamber", "referenceType": "analytical", "referenceTypeLabel": "Analytical", "reference": "exact one-dimensional solutions", "result": "duct: |T| = 1.0000; chamber: within 0.36 dB below 0.4 of the first cross-mode cut-on, the rest is the known limit of the 1-D theory", "url": "https://spectrasimulations.com/validation/#exact-1d" }, { "id": "il-radiation", "area": "acoustics", "case": "Straight pipe with radiation domains", "referenceType": "analytical", "referenceTypeLabel": "Analytical", "reference": "analytic power", "result": "insertion loss within 0.0006 dB", "url": "https://spectrasimulations.com/validation/#il-radiation" }, { "id": "pipe-re1e4", "area": "flow", "case": "Turbulent pipe flow, Re 10⁴", "referenceType": "other", "referenceTypeLabel": "Other reference", "reference": "published validation of a commercial CFD service (friction factor 0.0309)", "result": "pressure drop +9.7 % (entrance region of a uniform-inlet pipe against a developed-flow reference)", "url": "https://spectrasimulations.com/validation/#pipe-re1e4" }, { "id": "elbow-90", "area": "flow", "case": "90° pipe elbow, water", "referenceType": "code-to-code", "referenceTypeLabel": "Code-to-code", "reference": "commercial finite-element CFD model (405 Pa between two planes)", "result": "+8 % with the less diffusive momentum scheme on the same mesh (+18 % with the default scheme)", "url": "https://spectrasimulations.com/validation/#elbow-90" }, { "id": "y-splitter", "area": "flow", "case": "Symmetric Y-splitter", "referenceType": "symmetry", "referenceTypeLabel": "Symmetry", "reference": "symmetry", "result": "flow split 50/50 within 1 %", "url": "https://spectrasimulations.com/validation/#y-splitter" }, { "id": "transient-vs-steady", "area": "flow", "case": "Transient against steady, coarse pipe", "referenceType": "self", "referenceTypeLabel": "Self-consistency", "reference": "the steady result", "result": "14.2 Pa against 15.4 Pa", "url": "https://spectrasimulations.com/validation/#transient-vs-steady" }, { "id": "hot-pipe-700k", "area": "heat-transfer", "case": "Insulated hot pipe, 700 K", "referenceType": "analytical", "referenceTypeLabel": "Analytical", "reference": "analytical heat-transfer correlations", "result": "temperature drop within 2.8 % (cylindrical reference); energy balance 0.017 %", "url": "https://spectrasimulations.com/validation/#hot-pipe-700k" } ] }