The relationship between induced three-dimensional vortical structures in the wake and the drag of a profiled blunt trailing edge body
Bibliographic record
Abstract
Three-dimensional wake forcing is applied to a profiled blunt trailing edge body from synthetic jet arrays distributed symmetrically on both sides of the body. The effect on the wake is experimentally studied at Reynolds numbers based on body thickness, $d$ , of $2500 \leqslant Re_d=u_\infty d/\nu \leqslant 5000$ in the turbulent wake regime. The exits of the synthetic jets are rectangular slots and are oriented spanwise to the cross-flow with a uniform spacing of $2.4d$ . The forcing causes spanwise variations in the separated shear layers, leading to the von Kármán vortices tilting and forming coherent streamwise vortex loops. This reorientation of the wake vorticity is associated with the attenuation of the vortex street and drag reduction, consistent with previous studies of spanwise perturbations to wakes. The effect of forcing amplitude on the drag and wake structure is examined. It is found that the mean shedding frequency is constant across the span in all cases, indicating that the forced wake has a periodic organised structure. The greatest drag reduction of approximately 25 % is achieved when the vortical structures emitted by the jets penetrate up the edges of the boundary layers of the body, which occurs at velocity ratios (defined from the mean jet exit velocity during expulsion) of about 3 when $Re_d=2500$ and about 2 when $Re_d=5000$ . This study presents evidence that the forcing effectiveness is maximised when the vortex street is most tilted into the streamwise direction.
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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 | 0.002 | 0.001 |
| 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".