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Record W34668517

Unsteady Flows and Airfoil-Vortex Interaction

2003· article· en· W34668517 on OpenAlexaff
Mahmoud Mamou, M. Khalid

Bibliographic record

VenueDefense Technical Information Center (DTIC) · 2003
Typearticle
Languageen
FieldEngineering
TopicComputational Fluid Dynamics and Aerodynamics
Canadian institutionsNational Research Council Canada
Fundersnot available
KeywordsAirfoilStarting vortexVortexMechanicsPhysicsAngle of attackWakeBurgers vortexLeading edgeHorseshoe vortexRelative windAerodynamicsVortex sheddingClassical mechanicsVorticityVortex ringReynolds numberTurbulence
DOInot available

Abstract

fetched live from OpenAlex

Unsteady flows past two airfoils in tandem placed in a shock tube flow field have been studied using Navier-Stokes equations. An implicit Global Newton iterative procedure is applied for time-accurate solution of the transient flow field. This study is primarily motivated by a need to understand the aerodynamic implications of the blade-vortex interaction in the rotor flow field of a helicopter. To simulate the vortex effects in 2D, a streamwise moving shock wave is imposed immediately upstream of the leading edge of the lead airfoil, which is pitched at an angle of attack of -20 degrees. The lead airfoil is used to generate a vortex that can be lifted off and convected downstream until it reaches the trailing test airfoil. After the passage of the shock wave over the lead airfoil, a nearly symmetric vortex is generated. This vortex then separates at the trailing edge and convects downstream at the freestream velocity towards the aft airfoil. To avoid numerical dissipation, a refined grid is used along the vortex path. For the aft airfoil, it is observed that the passage of the vortex has notable effects upon its aerodynamic characteristics. It is further noted that the vortex is followed by the lead airfoil wake, which splits later on into a series of smaller vortices. Owing to the high angle of attack of the lead airfoil, the viscous flow underneath seems to progressively grow behind the shock wave resulting in a separation. The flow field is seen to comprise a complex pattern of incident and reflected compressibility waves from the walls, which interact with the separated flow present on the lower airfoil surface. (12 figures, 10 refs.)

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 imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.489
Threshold uncertainty score0.602

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.007
GPT teacher head0.208
Teacher spread0.201 · 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 teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
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

Citations0
Published2003
Admission routes1
Has abstractyes

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