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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-431-1

ISBN Online: 978-1-56700-430-4

First Thermal and Fluids Engineering Summer Conference
August, 9-12, 2015 , New York City, USA

Investigation of Dynamic Hybrid RANS-LES Modeling for Compressible Turbulent Flows

Get access (open in a dialog) pages 165-186
DOI: 10.1615/TFESC1.asp.013011

Аннотация

Interior and exterior flowfields of hot, supersonic aircraft engine nozzles display complex flow features including attached turbulent boundary layers and separated turbulent shear layers. Effective design requires accurate prediction of these features using advanced computational fluid dynamics techniques. This paper presents results for two relevant validation test problems for high-speed nozzle analysis. The simulations used a novel dynamic hybrid RANS/LES (DHRL) modeling framework coupled to an advanced low-dissipation numerical scheme within the Loci-CHEM finite-volume flow solver. Results are presented for unsteady flow simulations of free-shear and wall-bounded flows on structured and unstructured grid topologies. Three modeling approaches are investigated: implicit LES, conventional hybrid RANS/LES in which turbulence model terms are functions of local mesh size, and a dynamic hybrid RANS-LES (DHRL) scheme that smoothly blends the boundary between RANS and LES regions of the flow field. The simulations also compared two numerical reconstruction schemes used within a Roe flux method: a traditional least-squares gradient method with standard limiting and a new optimization-based gradient reconstruction (OGRE) low-dissipation method. Results from computations using the DHRL framework with the OGRE scheme showed good agreement, particularly when compared to the traditional methods, to experimental mean streamwise velocity profiles as well as experimental fluctuating RMS velocities.