On the turbulent flow characteristics of wall-attaching synthetic jets at varying offset height ratios
Bibliographic record
Abstract
This study investigates the influence of offset height ratio on the unsteady flow characteristics and coherent structures of wall-attaching synthetic jets using improved delayed detached eddy simulations. The simulations were conducted at a Reynolds number based on the average jet-exit velocity and nozzle diameter of Re=565, with an actuation frequency of 300 Hz. Four offset ratios (G/d=1, 2, 3, and 4, where G is the distance from the nozzle centerline to the bottom wall and d is the nozzle diameter) and a reference free synthetic jet (FSJ) were examined using instantaneous, phase-averaged, and time-averaged statistics, including Q-criterion, vortex-core circulation tracking, and proper orthogonal decomposition (POD). The results show that reducing G/d promotes stronger jet deflection and earlier attachment of the synthetic jet on the wall, leading to the development of a wall synthetic jet. At G/d=1, the vortex rings attach almost immediately on the wall, inducing strong spanwise stretching, vorticity redistribution, and rapid breakdown and decay of the jet. Increasing the offset ratio to G/d=2 delays wall attachment but introduces lower shear layer asymmetry that alters the evolution of the counter-rotating vortex pair. For G/d=3 and 4, the vortex evolution and the flow field are similar to the FSJ and also exhibit self-similarity in the far field. POD analysis reveals that, as the offset height ratio decreases, the strong jet-wall interactions significantly increase the range of turbulent scales, leading to an increased modal requirement in flow field reconstruction.
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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".