| Velocity (m/s) | Efficiency | ||||
| Constant-Diameter | Converging | Diverging | Converging-Diverging | Backward-Facing Step | |
| 0.3 | 5.54% | 6.66% | 5.54% | 6.48% | 5.51% |
| 0.5 | 5.79% | 7.63% | 5.80% | 7.20% | 5.51% |
| 0.8 | 6.39% | 8.33% | 6.44% | 6.33% | 5.51% |
| 1.0 | 6.80% | 3.97% | 6.83% | 2.97% | 5.52% |