| SI.Length | dimension | 0.01 | Characteristic dimension (e.g., hydraulic diameter) |
| SI.Area | crossArea | 0.25*Modelica.Constants.pi*dimension*dimension | Cross-sectional area |
| SI.Length | perimeter | Modelica.Constants.pi*dimension | Wetted perimeter |
| SI.Length | dlength | 1.0 | Pipe length |
| SI.Angle | angle | 0.0 | Vertical angle from the horizontal (-pi/2 < x <= pi/2) |
| SI.Length | dheight | dlength*sin(angle) | Height change (port_b - port_a) |
| SI.Height | roughness | 2.5e-5 | Average height of surface asperities |
| Units.NonDim[2] | ks | | Geometric correction coefficients: {laminar, turbulent} |
