Efficient Computation of Large Pitch Ratio Transonic Flow in a Fan With Inlet Distortion
Bibliographic record
Abstract
Modeling the unsteady flow of a fan subject to an inlet distortion is computationally expensive due to the need to model the full-annulus. Using the Fourier Transformation (FT) method in ANSYS CFX, which recognizes phase-shifted periodic boundary conditions, the fan inlet distortion simulation can be achieved efficiently by solving just two passages. The FT method can handle very large inlet distortion to blade passage pitch ratios such as the case of the problem simulated in this work. The analysis considers transonic flow through a fan with high bypass ratio subjected to an inlet total pressure distortion. The inlet disturbance traverses the inlet once per revolution and is intended to simulate the inlet flow distortion seen by an aircraft engine fan during take-off conditions. The pressure ratio across the fan is chosen so that the fan moves from a started to un-started condition as the disturbance moves past the inlet. This condition will provide a rigorous test of the FT method. The FT method is validated by comparing to the equivalent full-annulus unsteady solution. The FT unsteady solution compares remarkably well with the reference solution and is able to reproduce the detailed dynamics of the shock movement. Moreover, the solution from the FT method is also able to reproduce the efficiency, viscous effects and blade loading from the full-annulus case. The FT solution is obtained with a 5X reduction in CPU time and a 10X reduction in memory requirement.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".