Numerical Simulations of Internal Gravity Wave Breaking in the Middle Atmosphere: The Influence of Dispersion and Three-Dimensionalization
Bibliographic record
Abstract
A series of new analyses of the problem of the evolution of the internal gravity wave field that is excited when a uniformly stratified fluid flows over monochromatic topography is presented.Results demonstrate that upward-propagating waves overturn and break when they reach sufficient amplitude.The breaking of the wave field may occur due to either one or the other of two main effects, namely, the instability of the propagating wave front and the instability of the wave established behind the advancing front.The analysis of the wavemean flow momentum transfer process reveals significant differences between these results and the predictions of two main gravity wave drag parameterization schemes (viz., those based upon so-called saturation theory and the spectral theory based on the critical layer absorption mechanism) regarding the dynamics of wave breaking and the spatial distribution of the resulting momentum transfer.The vertical extent and structure of the breaking region and, hence, the momentum transfer from the wave field to the mean flow, are shown to be highly sensitive to the governing parameter aN/U (U and N are, respectively, the velocity and buoyancy frequency characteristic of the upstream incident flow, while a is the wavelength of a quasi-topographic forcing).This nondimensional parameter provides a measure of the importance of nonhydrostatic effects.When the flow is allowed to access the third spatial dimension, the simulations demonstrate that it develops intense three-dimensional motions in the regions of wave breaking.An instability first appears in the form of streamwise-oriented vortices of alternating sign that are consistent with typical convective instability patterns observed previously by different authors.It was observed, however, that two-dimensional coherence of the main flow is still maintained at the coarse-grain scale although the instability does lead to the onset of small-scale turbulence.
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 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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".