Supersonic Jet Impingement on a Cylinder and Characterization of the Resulting Deflected Jets
Bibliographic record
Abstract
The interaction between a mildly underexpanded supersonic jet and a single cylinder was studied experimentally at laboratory scale by using the schlieren technique coupled with high-speed photography and pitot pressure measurements. This study was motivated by the need to optimize sootblowing operation in kraft recovery boilers. The effects of the transverse distance between the jet and cylinder centerlines (eccentricity), nozzle–cylinder distance, and cylinder size on jet–cylinder interaction were determined. Results show that upon impingement on a cylinder, a supersonic jet deflects at an angle and creates a weaker supersonic jet that we refer to as a “secondary” jet. The angle and strength of the deflected or secondary jet depend on the eccentricity between the primary jet and cylinder centerlines. When a jet impinges on a cylinder of diameter comparable to that of the jet or smaller, secondary jets form not only when the cylinder is placed close to the nozzle (in the stronger portion of the jet) but also when the cylinder is placed far away (in the jet's weaker portion; up to 20–24 nozzle exit diameters in the present study). Changing the eccentricity slightly results in a significant change in the secondary jet characteristics. For a cylinder much larger than the jet, secondary jets do not form at zero eccentricity (head-on impingement); the eccentricity at which they begin to form increases with the cylinder size. A study of the secondary jets shows that they spread out much more than the primary jet and are sheet- or fan-like with an oblong, oval cross section. The centerline pitot pressure of the secondary jets remains as high as the primary jet for a considerable distance from the tube only during weak interaction between the primary jet and the cylinder (i.e., during strongly eccentric/off-centerd impingement). As the interaction between the primary jet and the cylinder intensifies at lower eccentricities, the maximum centerline pitot pressure of the secondary jet decreases, and the pitot pressure decreases more quickly with distance from the tube.
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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".