SAE 30 mineral oil
A typical SAE 30 mineral engine oil at 40 °C — about 0.088 Pa·s, some ninety times the viscosity of water at 20 °C.
| Phase | Liquid |
| Temperature range | Single published state at 40 °C |
| Source | SAE J300 grade bands; density and thermal properties typical of paraffinic mineral base stock |
Published at 40 °C. This fluid has no temperature curve in this library — the values below are a single measured state, not a function.
| Density | 876 kg/m³ |
| Dynamic viscosity | 88 mPa·s |
| Specific heat | 1.9 kJ/(kg·K) |
| Thermal conductivity | 0.145 W/(m·K) |
| Kinematic viscosity ν = µ/ρ | 100.46 mm²/s |
| Prandtl number Pr = cpµ/k | 1,153 |
Every fluid property in these opens already filled, all from the same state — so a density and a viscosity in one calculation always describe the same fluid at the same temperature.
Reynolds Number
ρ = 876μ = 88
Poiseuille's Law
μ = 88
Stokes' Drag (F = 6πμrv)
μ = 88
Learning zone
Lubricating oils are graded by kinematic viscosity, not dynamic. An SAE 30 monograde runs roughly 95–110 cSt at 40 °C and 9.3–12.5 cSt at 100 °C; multiplying 100 cSt by a density near 876 kg/m³ gives about 0.088 Pa·s. The SAE numbers are grade BANDS, not measurements, and two SAE 30 oils from different refiners can legitimately differ by 15 %.
It is pinned at 40 °C because that is the reference temperature the grade is defined at, but the temperature sensitivity is the whole story of lubrication and this single value hides it badly. The same oil is around 0.4 Pa·s at 20 °C and 0.01 at 100 °C — a factor of forty — which is why cold starts are where engines wear and why multigrade oils exist. A 10W-30 is not "thicker when hot"; it is a base oil that behaves like a 10-weight at cold-crank temperature and a 30-weight at operating temperature, achieved with viscosity-index improvers. If your calculation is not at 40 °C, use a data sheet.
The constants library carries these at a single stated temperature, with their uncertainty and provenance. The table above is the same substance as a function.