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Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
December, 14-17, 2023, Bihar, India

Development of an Interpolated RANS-LES Solver for Turbulent Heat Transfer

Get access (open in a dialog) DOI: 10.1615/IHMTC-2023.640
pages 391-396


Hybrid RANS-LES models are suitable for simulating high Reynolds number wall-bounded turbulent flows for thermofluidic applications. In such models, the subgrid stress/flux model switches from RANS (Reynolds Averaged Navier Stokes) near the wall to LES (Large Eddy Simulation) away from the wall. In typical hybrid RANS-LES models, the skin friction and heat transfer coefficients are underpredicted within turbulent boundary layers due to "modeled stress/flux depletion". In this work, a novel Interpolated RANS-LES (IRL) model has been formulated for flows involving turbulent heat transfer. Governing equations for RANS and LES models have been solved on the same computational domain. Based on the distance from the wall, the domain is discretized into near-wall and free-stream regions, along with a "hybrid" region sandwiched between the free-stream and near-wall region. The mean stress (heat flux) from RANS is imposed on the momentum (energy equation) in the near-wall region. In the hybrid region, the mean stress (heat flux) is interpolated between the mean resolved stress (heat flux) predicted by LES in the free stream region and the Reynolds stress (heat flux) predicted by RANS in the near wall region. The interpolation of Reynolds stress and heat flux in hybrid region is carried out via solution of a Laplace equation. The interpolated stress/flux in the hybrid region is used to correct the mean stress/flux in the region. The non-isothermal IRL solver has been implemented in OpenFoam v7 and validated against DNS (Direct Numerical Simulation) data for turbulent heated channel. Unlike results from Detached Eddy Simulations (DES), modeled stress/flux depletion is not observed in the IRL solver.