Extension of the amplification factor correlations for circular cylinder flow

Abstract

The current correlations employed in the AFT model have previously shown an improvement in predicting the flow past a circular cylinder when compared to fully-turbulent approaches for sub-critical, critical and super-critical regimes. However, the transition onset prediction and consequently the turbulent separation point prediction is poor when compared to experimental or large-eddy simulation data for the critical and super-critical regimes. In addition, in the trans-critical regime the model is not capable of producing the transition (without the appearance of laminar separation bubble) on the upstream face of the circular cylinder. This paper aims to produce new correlations for the critical Reynolds number and the amplification factor transport from a stability analysis using velocity profiles for flow past a circular cylinder, along with proportionality functions between Rev and Reθ, and the local shape factor (HL) and the integral shape factor (H ₁₂). Boundary layer growth at sub-critical and super-critical regime show the over-prediction of the correlation proposed by the original AFT when predicting the integral shape-factor in terms of the local shape-factor, which originally assumes θ of the order of (formula presented). This relationship is not followed for a boundary layer developing over a circular cylinder and consequently, the vorticity Reynolds number to momentum-thickness Reynolds number ratio (Kv) is under-predicted by the original correlations. Furthermore, the differences on the development of the boundary layer over the circular cylinder surface also influence the behavior of the critical momentum-thickness Reynolds number (Reθ, _,cr), which is delayed due to the acceleration region on the upstream face, as well as the growth of the most unstable frequencies for a given velocity profile. Results with the use of updated correlations proposed in this paper show how the sub-critical regime is not influenced by the correlations since transition is not present. However, the separation point is delayed when compared to a fully-laminar prediction. In the super-critical regime, predictions with the updated correlations show that the transition onset has a better agreement with LES data from literature.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata

Altmetrics