Roughness Models
The Drainage and Utilities solver uses the Manning's equation to evaluate the friction slope term, Sf:
| n | = | Manning coefficient for friction | |
| µ | = | unit conversion factor (1.49 for US Customary and 1.0 for SI units) | |
| R | = | hydraulic radius | |
| K | = | flow conveyance factor |
The Manning’s n is a user-defined value that introduces the effects of conduit, channel, or gutter roughness. The K that is actually applied for a segment between two interpolated locations along the computational stream is evaluated by averaging the K values computed for the two locations.
For more information on the application of this roughness model, see "Implementations" .