Effect of Gerlach Cross-Section on S-Duct Inlet Performance in High Subsonic Flow
Bibliographic record
Abstract
Abstract It was hypothesized in literature that Gerlach re-shaping of the cross-section of S-duct inlet bends may reduce the transverse pressure gradient and mitigate or eliminate flow separation. This paper presents an internal performance evaluation of an S-duct diffuser with Gerlach cross-sectional area compared to a baseline S-duct. The generic baseline test article was a rectangular-entrance S-duct transitioning to a circular exit, a configuration typical of single-engine air vehicles. The important geometric parameters were exit-to-entrance area ratio of 1.57 and an offset-to-length ratio of 0.37. The performance of the intake was evaluated at Ma = 0.80 by measuring the axial static pressure distribution, exit total pressure and three-dimensional velocity at the aerodynamic interface plane. The measurements were used to evaluate and compare the aerodynamic performance of the S-duct variants. The geometries and flow conditions were also simulated numerically and validated using experimental performance metrics. The static pressure recovery decreased for the Gerlach S-duct; however, total pressure recovery improved. This work will contribute to the development of improved performance for S-duct inlets and for predicting the performance of aero-engines and air vehicles at high-subsonic flight conditions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".