Analysis of shock dynamics in supersonic intakes
Bibliographic record
Abstract
This work investigates fluid mechanical processes involving movement of shock waves inside channels. In particular, the prediction and control of shock motion in intakes is of great importance to high-speed flight and future spacecraft engines--it is a fundamental problem whose solution currently enjoys a high degree of interest. In the first part of the thesis, an analytical, numerical, and experimental study is performed in two-dimensions to assess the quasi-steady flow starting characteristics in an external-compression ramp-type intake. Using the popular model based on common understanding in the field and consistent with well-cited literature, it is shown that the traditional model based on one-dimensional flow across a planar shock is inaccurate. To remedy this, a novel analytical model is presented to predict off-design self-starting behaviour using a curved shock wave. The analytical results are supported by the numerical evidence from CFD simulations as well as by the experimental evidence; taken together, these results constitute overwhelming evidence supporting the arguments presented. In the second part of the thesis, an analytical and numerical study is performed in the unsteady, quasi-one-dimensional setting to assess the feasibility of predicting shock dynamics inside an intake using a simple, approximate, yet representative model. There is very little widely-available knowledge on impulsive flow starting in the literature, and there is no existing theory for analytically predicting impulsive flow starting phenomena discussed here. The well-known Chester-Chisnell-Whitham formulation is extended using a novel model (labelled lifting isentrope); it is effectively a provision for non-uniform, unsteady flow upstream of the shock wave. It is found that a singularity exists in the CCW model, which prevents its application to problems in impulsive flow starting. There is little or no literature on this singularity. To resolve these issues, a novel for
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".