Product: GeoStudio Flow - SEEP/W, TEMP/W, CTRAN/W, AIR/W
Occurrence:
I want to know the difference between the rate and flux terms used in the GeoStudio heat and mass transfer products.
Resolution:
Significant effort has been made to use nomenclature that is consistent with that accepted by the general scientific community. The term rate is used to describe the ratio between two related quantities (e.g. volume / time). The term flux is exclusively used to describe a quantity (e.g. a flow rate) that passes through a surface (or area).
The terms, their definition, and associated units are provided below:
|
Term |
Definition |
SI Units |
|
Water Rate |
Volume of Water / Time |
m3/s |
|
Water Flux |
Water Rate / Area |
m3/s/m2 = m/s |
|
Heat Rate |
Energy / Time |
J/s |
|
Heat Flux |
Heat Rate / Area |
J/s/m2 |
|
Solute Mass Rate |
Mass / Time |
g/s |
|
Solute Mass Flux |
Solute Mass Rate / Area |
g/s/m2 |
|
Gas Mass Rate |
Mass / Time |
g/s |
|
Gas Mass Flux |
Gas Mass Rate / Area |
g/s/m2 |
|
Air Rate |
Volume of Air / Time |
m3/s |
|
Air Flux |
Air Rate / Area |
m3/s/m2 = m/s |
Notes:
In GeoStudio, the area associated with a given node (for example that a flux is applied to) is the product of the element thickness and the sum of the mid-distance between the nodes on each side of the node of interest (refer to the figure below).
