Assessment of the Symmetry-Preserving Regularization model on complex flows using unstructured grids O. Lehmkuhl a,b,∗ , R. Borrell b , I. Rodr´ ıguez a , C.D. P´ erez-Segarra a , A. Oliva a a Centre Tecnol` ogic de Transfer` encia de Calor, Universitat Polit` ecnica de Catalunya,ETSEIAT, Colom 11, 08222 Terrassa (Barcelona), Spain. b Termo Fluids, S.L. Mag´ ı Colet, 8, 08204 Sabadell (Barcelona), Spain. Abstract Traditionally, turbulence modelling of industrial flows in complex geometries have been solved using RANS models and unstructured meshes based solvers. The lack of precision of RANS models in these situations and the increase of computational power, together with the emergence of new high-efficiency sparse parallel algorithms, have made possible the use of more accurate tur- bulent models such as Large Eddy Simulation (LES). Recently, relevant im- provements on turbulence modelling based on regularization techniques for the convective (non-linear) terms have been developed. They basically alter the convective terms to reduce the production of small scales of motion by means of vortex-stretching and preserving exactly all inviscid invariants. If symmetry and conservation properties of the convective terms are preserved, this yields a novel class of regularizations (i.e. symmetry-preserving regular- ization models). These models restrain the convective production of small scales in an unconditional stable manner, meaning that the velocity cannot ∗ Tel: +34 93 739 8192; fax: +34 93 739 8101 Email address: cttc@cttc.upc.edu (A. Oliva) Preprint submitted to Computers and Fluids March 19, 2012