Hybrid turbulence model simulations of hemisphere-cylinder geometry

A. Gross, H. F. Fasel

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

When low aspect ratio geometries such as submarines, torpedoes, or missiles are operated at large angles of attack three-dimensional separation will occur on the leeward side. Separation incurs losses and can result in undesirable unsteady forces. An improved understanding of three-dimensional separation is desirable as it may open the door to new methods for the control or prevention of separation. Numerical simulations of three-dimensional separation can provide detailed insight into instability mechanisms and the resultant flow structures. For most technical applications the Reynolds numbers are too high for direct numerical simulations and lower-fidelity approaches such as hybrid turbulence models become attractive. In this paper a hybrid turbulence model blending strategy is employed that adjusts the model contribution according to the local grid resolution. The strategy is validated for two-dimensional plane channel flow at Reτ=395 and 2000. The model is then employed for simulations of a hemisphere-cylinder geometry at 10° and 30° angle of attack. The simulations demonstrate satisfactory model performance over a wide range of Reynolds numbers (5×104<ReD<5×105). A nose separation bubble is captured for the lower Reynolds numbers and leeward vortices are observed for 30° angle of attack regardless of Reynolds number.

Original languageEnglish (US)
Pages (from-to)28-38
Number of pages11
JournalInternational Journal of Heat and Fluid Flow
Volume54
DOIs
StatePublished - Aug 1 2015

Keywords

  • Computational fluid dynamics
  • Hybrid turbulence model
  • Leeward vortices
  • Reynolds number scaling
  • Three-dimensional separation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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