| SI.Length | lengths | ones(nNodes) | Length of node segment |
| SI.Length | dimensions | if use_Dimensions then zeros(nNodes + 1) else 4*crossAreas./perimeters | Characteristic dimension (e.g., hydraulic diameter) |
| SI.Area | crossAreas | pi*dimensions.*dimensions./4 | Cross-sectional flow areas |
| SI.Length | perimeters | 4*crossAreas./dimensions | Wetted perimeters |
| SI.Height | roughnesses | fill(2.5e-5, nNodes + 1) | Average heights of surface asperities |
| SI.Length | dheights | fill(0, nNodes) | Height(port_b) - Height(port_a) distributed by flow segment |
| SI.Length | height_a | 0 | Elevation at port_a: Reference value only. No impact on calculations. |
| SI.Length | height_b | height_a + sum(dheights) | Elevation at port_b: Reference value only. No impact on calculations. |
| Real | dxs | lengths/sum(lengths) | Fractional lengths |
