Description
Return Stokes particle relaxation time with a supplied slip factor.
Particle and droplet terms depend on size representation, weights, density, drag and logarithmic-bin conventions. A spherical growth or low-Reynolds approximation is a local model term rather than a measured size distribution, composition or health/exposure assessment.
Return Stokes particle relaxation time with a supplied slip factor.
When to use this tool
Use Aerosol Stokes Relaxation Time Term when checking the stated particle, droplet, drag, growth or bin-basis convention.
How to use the tool and how it works
- Enter particleDensity, diameter, slipCorrection, viscosity. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read relaxationTime. Use the output convention below.
Return Stokes particle relaxation time with a supplied slip factor. Require density/diameter >= 0, viscosity/slipCorrection > 0; tau = density*diameter²*slipCorrection/(18*viscosity).1
Stokes drag describes a sphere in an appropriate viscous-flow regime. The low-Reynolds assumption must be checked separately before using a derived transport scale.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| particleDensity | Particle Density | Required. Finite number; minimum 0. |
| diameter | Diameter | Required. Finite number; minimum 0. |
| slipCorrection | Slip Correction | Required. Finite number; strictly above 0. |
| viscosity | Viscosity | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| relaxationTime | Relaxation Time | Required. Finite number. |
{
"input": {
"particleDensity": 1800,
"diameter": 0.00001,
"slipCorrection": 1,
"viscosity": 0.00002
},
"output": {
"relaxationTime": 0.0005
}
}Limitations and assumptions
- This assumes an appropriate spherical low-Reynolds drag model; slip correction, actual particle properties and transport conditions are not derived.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use verified particle measurements and an appropriate complete distribution/transport model with justified material, shape and flow assumptions for atmospheric inference.
References
Similar or alternative tools
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