KNUDSEN
Excel Usage
=KNUDSEN(path, L)path(float, required): Mean free path between molecular collisions [m]L(float, required): Characteristic length [m]
Returns (float): Knudsen number [-]
Examples
Example 1: Knudsen number with path=1e-10, L=0.001
Inputs:
| path | L |
|---|---|
| 1e-10 | 0.001 |
Excel formula:
=KNUDSEN(1e-10, 0.001)Expected output:
1e-7
Example 2: Continuum flow regime (Kn << 1)
Inputs:
| path | L |
|---|---|
| 1e-8 | 0.01 |
Excel formula:
=KNUDSEN(1e-8, 0.01)Expected output:
0.000001
Example 3: Transition flow regime (Kn ~ 1)
Inputs:
| path | L |
|---|---|
| 0.00001 | 0.00001 |
Excel formula:
=KNUDSEN(0.00001, 0.00001)Expected output:
1
Example 4: Free molecular flow regime (Kn >> 1)
Inputs:
| path | L |
|---|---|
| 0.001 | 0.000001 |
Excel formula:
=KNUDSEN(0.001, 0.000001)Expected output:
1000
Python Code
from fluids.core import Knudsen as fluids_Knudsen
def knudsen(path, L):
"""
Calculate the Knudsen number.
See: https://fluids.readthedocs.io/fluids.core.html#fluids.core.Knudsen
This example function is provided as-is without any representation of accuracy.
Args:
path (float): Mean free path between molecular collisions [m]
L (float): Characteristic length [m]
Returns:
float: Knudsen number [-]
"""
try:
path = float(path)
L = float(L)
if path < 0:
return "Error: Mean free path must be non-negative"
if L <= 0:
return "Error: Characteristic length L must be positive"
result = fluids_Knudsen(path, L)
return float(result)
except (TypeError, ValueError) as e:
return f"Error: Invalid input - {str(e)}"
except Exception as e:
return f"Error: {str(e)}"