| 1. |
- Basara, B., et al.
(författare)
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Near-Wall Formulation of the Partially Averaged Navier-Stokes Turbulence Model
- 2011
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Ingår i: AIAA Journal. - : American Institute of Aeronautics and Astronautics (AIAA). - 1533-385X .- 0001-1452. ; 49:12, s. 2627-2636
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Tidskriftsartikel (refereegranskat)abstract
- The variable-resolution partially averaged Navier-Stokes bridging strategy is applied to the four-equation k-epsilon-zeta-f turbulence model. In this approach, the popular two-equation model is enhanced with an additional transport equation for the velocity scale ratio zeta and an equation for the elliptic relaxation function f for the purpose of improved near-wall behavior. By using the elliptic relaxation technique to model the wall blocking effect, the new four-equation partially averaged Navier-Stokes model retains the simplicity of the previous two-equation partially averaged Navier-Stokes versions but significantly improves predictions in the near-wall region. The proposed partially averaged Navier-Stokes k-epsilon-zeta-f model is evaluated in a turbulent channel flow and flow around a three-dimensional circular cylinder mounted vertically on a flat plate. The results clearly show benefits of the improved near-wall modeling and extend partially averaged Navier-Stokes applicability to a broader range of smooth bluff-body separated flows.
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| 2. |
- Basara, B., et al.
(författare)
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Performance analysis of partially-averaged navier-stokes method for complex turbulent flows
- 2011
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Ingår i: 6th AIAA Theoretical Fluid Mechanics Conference, Honolulu, 27 - 30 June 2011. - Reston, Virigina : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (refereegranskat)abstract
- The paper evaluates the performance of the Partially-Averaged Navier-Stokes (PANS) method on complex industrial Computational Fluid Dynamics (CFD) applications. The PANS method changes seamlessly from Reynolds-Averaged Navier-Stokes (RANS) to the Direct Numerical Solution (DNS) of the Navier-Stokes equations and supports any filter width or scale resolution and therefore, it has potential to be efficient tool to solve large and complex applications on available computational resources. The PANS variant, which is used in the present study, is based on the RANS k-ε-ζ-f model (v2/k-f model). In the work presented here, the filter width is controlled by specifying one control parameter: unresolved-to-total ratios of kinetic energy fk. Furthermore, this parameter is defined based on the grid spacing. A dynamic update of fk at each computational point and at the end of every time step makes the computational procedure very simple and attractive for industrial CFD. The model's performance is shown for complex CFD cases: an external car aerodynamics, a train aerodynamics and engine intake ports.
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| 3. |
- Pavlovic, Z., et al.
(författare)
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CrRb: A molecule with large magnetic and electric dipole moments
- 2010
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 81:5
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Tidskriftsartikel (refereegranskat)abstract
- We report calculations of Born-Oppenheimer potential energy curves of the chromium-rubidium heteronuclear molecule ((CrRb)-Cr-52-Rb-87), and the long-range dispersion coefficient for the interaction between ground state Cr and Rb atoms. Our calculated van der Waals coefficient (C-6 = 1770 a.u.) has an expected error of 3%. The ground state (6)Sigma(+) molecule at its equilibrium separation has a permanent electric dipole moment of d(e)(R-e = 3.34 angstrom) = 2.90 D. We investigate the hyperfine and dipolar collisions between trapped Cr and Rb atoms, finding elastic to inelastic cross section ratio of 10(2)-10(3).
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