Investigation Of The Nozzles' Spacing Impact On The Interference Of Unequal Parallel Round Jets: Large Eddy Simulation Study
Bibliographic record
Abstract
Twin parallel jets contain extensive range of industrial applications such as cooling systems and fuel injection systems. Entrainment of the ambient fluid into the jets' core is the key observation in majority of the applications which yields to raise in mixing owing to the larger momentum transfer. Despite several experimental and numerical studies in literature on twin planar jets, there have been small portion of numerical investigations devoted to the unequal parallel round jets. This paper aims to survey the effect of the jets' distance on the flow features of unequal round jets by large eddy simulation (LES) utilizing OpenFOAM package. The Reynolds numbers (Re) of unequal jets for all cases are set to 10,000 and 5,000 based on their same diameters and different jets' velocities. To analyze the effect of the distance between unequal twinjets, three spacings S/Djet= 1.1, 1.5 and 2 are considered. The LES results for a similar mesh quality including a single jet with the Re of 5,000 are evaluated by the available experimental data. The validation of current LES study proved well enough match in terms of radial and axial distributions of mean and r.m.s velocity profiles. In addition, to track the flow structures and jets' interference properly versus jet-spacing, two different passive scalars are ejected from left and right jets. The mean streamwise velocity profiles for three cases demonstrated that, near the jets' exit section, there is huge difference between the profiles and distant jets (for instance S/Djet=2) act independently. Getting away from jets exit, due to the interaction of two jets the velocity profiles for three cases become similar (~ 9D far from jet exit) with the asymmetrical bell shape. In addition, the maximum points position of jets' velocity profiles (for both left and right) remain almost constant as moving toward downstream in all cases. The mean concentration contours for strong and weak jets proved that the strong jet is not affected by the weak one even for very close vicinity jets (small distance). A remarkable observation is that the position of maximum point of weak jet's passive scalar is moving outward direction as getting far from the jets exit. Whereas, as the jets' distance increases the weak jet will be entrained strongly toward the strong jet. In addition, as the distance between the jets reduces, the strong jet pushes away the maximum point of the weak jet's passive scalar more intensely.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".