A critical look at the criticality of sediment-propelled turbidity currents
Notice bibliographique
Résumé
In nature turbidity currents are common, and in the deep marine are the principal sediment transporting agents that build up the largest sediment accumulations on Earth. However these powerful currents are notoriously destructive, and as a consequence have been largely unexplored. Accordingly, researchers have turned to analyzing them in the lab. Here it is easy to form a suspended-sediment-propelled turbidity current but because of their inherently dense nature these flows are not amenable to conventional sampling instrumentation. As a consequence most researchers have used variably concentrated saline currents with the implicit assumption, or explicit statement, that they faithfully mimic the dynamics of sediment-propelled currents. Based on that work, two end member kinds of (saline) currents were identified, and differentiated on the basis of flow criticality: subcritical flows have a high velocity maximum below which density is vertically uniform (“plug-like”) and above which density decreases rapidly and shows minimal mixing with the overlying fluid; conversely, the velocity maximum of supercritical flows is located at the base of the current, density decreases exponentially away from the bed, and the current as a whole shows extensive vertical mixing. The question, therefore, is under similar hydraulic conditions, are the velocity and density profiles in saline currents representative of those formed in sediment-propelled turbidity currents? In this study, we created a variety of turbidity currents of varying velocity and sediment concentration. However unlike these other studies, this is the first to accurately measure the density profile (here a surrogate for sediment concentration) in natural, sediment-transporting turbidity currents using a medical grade CT scanner. Given similar hydraulic conditions, the two end-member profiles are controlled exclusively by particle size; specifically the velocity, density and mixing characteristics of fine grained runs were similar to subcritical saline flows whereas coarse-grained runs were similar to supercritical saline flows. Such differences in density and velocity structure will profoundly influence the vertical distribution of momentum through the current, and the degree of vertical mixing, which has important implication for the conservation of flow energy, and therefore run out distance of turbidity currents in the deep sea.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,035 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».