Numerical investigation of three-dimensional separation in internal and external flows

R. Jacobi, A. Gross, H. Fasel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

For Navy relevant geometries, separation of wall bounded flows is a highly complex phenomenon. Because of the relatively high Reynolds numbers involved, separation is always associated with considerable unsteadiness. This unsteadiness is caused by large coherent structures that are a consequence of hydrodynamic instability mechanisms of the mean flow. In addition, due to the shape of underwater vehicles (submarines, torpedoes, low aspect ratio lifting or control surfaces) the separation is three-dimensional (3D). The combination of three-dimensionality and unsteadiness results in a highly complex time-dependent topology of the separated region. In a combined numerical/experimental effort, we are studying laminar separation bubbles in external flows. For these simulations, we employ highly-resolved direct numerical simulations (DNS) to obtain a deeper understanding of the various physical mechanisms governing separation, transition, and reattachment of 3D bubbles. Ultimately, such understanding may pave the way for the development of effective and efficient strategies for preventing separation for practical applications. We are also evaluating hybrid turbulence models for high Reynolds number flows. In particular, we describe DNS, Reynolds-Averaged Navier-Stokes (RANS), and hybrid simulations of a turbulent square duct flow. Based on these simulations we decided on two hybrid strategies for simulating the asymmetric diffuser experiments that were conducted at Stanford University by J. Eaton et al. The first mean flow results look very encouraging. If successful, this research will result in hybrid models that are suitable for a wide variety of flow topologies and Reynolds numbers.

Original languageEnglish (US)
Title of host publicationDepartment of Defense Proceedings of the High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009
Pages96-105
Number of pages10
DOIs
StatePublished - Dec 1 2009
Event2009 DoD High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009 - San Diego, CA, United States
Duration: Jun 15 2009Jun 18 2009

Publication series

NameDepartment of Defense Proceedings of the High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009

Other

Other2009 DoD High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009
CountryUnited States
CitySan Diego, CA
Period6/15/096/18/09

ASJC Scopus subject areas

  • Computational Theory and Mathematics
  • Theoretical Computer Science

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    Jacobi, R., Gross, A., & Fasel, H. (2009). Numerical investigation of three-dimensional separation in internal and external flows. In Department of Defense Proceedings of the High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009 (pp. 96-105). [5729450] (Department of Defense Proceedings of the High Performance Computing Modernization Program - Users Group Conference, HPCMP-UGC 2009). https://doi.org/10.1109/HPCMP-UGC.2009.19