ECCOMAS 2024

A Generally Applicable Partially-Averaged Navier-Stokes Scale-Resolving Method

  • Basara, Branislav (AVL List GmbH)
  • Pavlovic, Zoran (AVL List GmbH)
  • Stipic, Marija (AVL List GmbH)

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Scale resolving turbulence methods are extremely attractive to CFD users, especially those involved in simulations of complex industrial flows. The turbulent approach, which is to be used as a general model for industrial flow simulations, is subject to ambitious requirements, and these are some of these conditions: a) The main calculation values must have a minimum dependency on the numerical mesh used and the results must not be worse than the results obtained with the industry standard RANS model on any calculation mesh b) The coefficients of the model must be adjusted during the calculation itself - there is no repetition of the calculation for the same mesh c) It must also be compatible with other physical models e.g. models for multiphase, spray, combustion etc. d) The quality of LES and DNS must be generated on computational meshes that fulfil the criteria for LES and DNS. The PANS approach formulated by Girimaji [1, 2] is designed to fulfil all these requirements. This approach seamlessly transitions from the Reynolds-Averaged Navier-Stokes (RANS) to the Direct Numerical Solution (DNS) of the Navier-Stokes equations, depending upon the prescribed cut-off length (filter width), where the cut-off resolution parameters are a ratio of unresolved to total kinetic energy fk and of unresolved to total dissipation f. There are several proposals on how to calculate fk with the formula using the total kinetic energy, as well as a recent approach by Basara, Pavlovic, and Girimaji [2] in which the resolved component, called the scale supply variable (SSV), is calculated with its own equation. This new PANS SSV variant enables efficient computations of applications with moving geometries, transient boundaries, and inherent instability, e.g., periodic fuel injection. The mentioned sub-variants of the basic PANS approach cover a wide range of applications, from the external aerodynamics of the vehicle to the calculation of moving geometries such as engines, pumps, compressors, etc., including calculations with models for spray, combustion, emissions, etc. Here we present all aspects of PANS calculations of complex flows and include some numerical details that can make the use of PANS even more attractive for such industrial applications. REFERENCES [1] S. Girimaji, R. Srinivasan, R., and E. Jeong, PANS Turbulence Models For Seamless Transition between RANS and LES Fixed Point Analysis and Preliminary Results, ASME paper FEDSM2003-45336, Hawaii, USA, 2003.