Effect of the Rear Geometry on the Flow Structure and Drag of the Ahmed Body
Bibliographic record
Abstract
Abstract There is a need for fuel-efficient vehicles to reduce greenhouse emission and minimize the range problem of electric vehicles. Aerodynamic drag reduction provides one of the cheapest but effective alternatives. Therefore, the development and analysis of new passive strategies that can modify the flow structure to improve aerodynamic performance are much needed. The present study aims to provide a passive drag reduction method using the standard 35° Ahmed body. The classic rectangular slanted surface is replaced with elliptical to study the effect of reear geometry on aerodynamic performance. The study is conducted using the ANSYS FLUENT software at a Reynolds number of 7.8 × 105, based on the height of the model. The SST k-omega model is applied to solve the Navier-Stokes equations. The results show that the elliptical model reduced the drag by 10% compared to the classic rectangular geometry. The cause of this drag reduction is associated with the large modification of the flow structure in the wake region. Also, the reverse flow is observed to shift towards the vertical base compared to the standard model, where it exits away from the vertical base. The drag reduction is found to correlated with the recirculation modification. Therefore, this study provides detailed data and analysis of wake modification and drag reduction processes.
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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".