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Record W2053958464 · doi:10.1260/0309-524x.37.1.105

Betz Limit Not an Exact Optimum

2013· article· en· W2053958464 on OpenAlexaff
S. P. Farthing

Bibliographic record

VenueWind Engineering · 2013
Typearticle
Languageen
FieldEngineering
TopicFluid Dynamics and Turbulent Flows
Canadian institutionsRemotely Operated Platform for Ocean Sciences
Fundersnot available
KeywordsWakeThrustRotor (electric)Trailing edgeLimit (mathematics)PhysicsMomentum (technical analysis)Control theory (sociology)MechanicsMathematicsMathematical analysis

Abstract

fetched live from OpenAlex

The Betz high speed ratio limit has not been derived in the complete generality that would prove it absolute for an unshrouded actuator. The assumed uniform wake or thrust loading is hard to prove optimal. Many authors also assume uniform flow at the rotor or equivalently the differential form of the momentum equation but neither is necessary in the derivation or in fact true. Calculations of the expanding vortex ring wake have indicated lower velocity at the rotor's edge and slightly higher in the center. It is shown that if the uniform wake is perturbed by a fraction of the same variation function, the Betz power coefficient is raised. The increase is very small for a Hawt but might be bigger for a 2D actuator with a larger variation function. Thus the Betz value is very close to a local optimum, but not exact or absolute.

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 imitation

Not 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.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.007
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.008
Threshold uncertainty score0.028

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.007
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.001
Bibliometrics0.0010.000
Science and technology studies0.0010.002
Scholarly communication0.0020.004
Open science0.0010.001
Research integrity0.0020.002
Insufficient payload (model declined to judge)0.0080.002

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.

Opus teacher head0.007
GPT teacher head0.171
Teacher spread0.164 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreEmpirical

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".

Quick stats

Citations5
Published2013
Admission routes1
Has abstractyes

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