Bibliographic record
Abstract
Sand bars having spacing equal to half the surface wavelength may be formed by the action of partially standing waves on an erodible bed. Here the stages of development of a patch of bars has been investigated in a wave tank, using rapid, accurate, ultra-sonic detection systems to monitor both the changing bed profile and the evolving surface wavefield. Initially, small-scale ripples formed on a (flattened) bed surface. These ripples varied in size according to position in the wave envelope, and had asymmetrical profiles due to asymmetry in the near-bed oscillatory motion. Vortex shedding from the ripples gave rise to regions of net sediment accumulation (bar crests) and erosion (troughs) linked to position in the wave envelope. The bars formed with wavelength satisfying the Bragg condition and with bar crests positioned downwave of the antinodes of elevation. As expected, this produced an increase in the overall reflection coefficient of the bar patch as the bars grew in height. The presence of the small-scale ripples had only a minor effect on the reflection coefficient, the flow being essentially inviscid away from the boundaries of the motion and the ripple wavelength being far smaller than the surface wavelength. However, the ripples played an important role in dissipating wave energy in the tank, wave dissipation factors being 3 or 4 times larger than equivalent values for laminar flow above a smooth bed. The present observations of the resonant interaction between surface waves and an erodible bed are believed to be the most detailed and accurate to have been reported to date.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.999 | 0.998 |
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; both teacher heads agree on what is shown here.
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".