A hybrid rans-les method with compressible k-omegaSSTSAS turbulence model for high Reynolds number flow applications

2015 Tehnički Vjesnik  
Original scientific paper Three-dimensional, compressible, viscous and transient transonic turbulent flow over the wing was simulated by a hybrid RANS-LES modelling method, combined with the compressible k-omegaSSTSAS turbulence model. This approach is based on dividing the contribution of the fluctuating and the averaged velocity fields in the subgrid tensor, and modelling each of them with its corresponding turbulent viscosity. The "RANS mode" is used in flow field domains which can be
more » ... which can be treated with acceptable accuracy as relatively steady, such as in the boundary layer, while the "LES mode" is applied in the dominantly unsteady regions, far from the wing. Discretization of the governing equations is performed by Finite Volume Method on unstructured mesh. The method has been verified on the Onera M6 wing. The parallelization is achieved by decomposing the mesh into sub-domains and using the Open MPI technology. The implementation of turbulence model has been done using OpenFOAM. The flow simulation was also performed using ANSYS Fluent, and the results of the two methods were compared mutually, and with the Onera M6 experiment. Hibridna RANS-LES metoda s kompresibilnim k-omegaSSTSAS turbulentnim modelom namjenjena analizi strujanja pri velikim Reynoldsovim brojevima Izvorni znanstveni članak Trodimenzionalno, kompresibilno, viskozno i nestacionarno transonično turbulentno strujanje oko krila modelirano je hibridnom RANS-LES metodom, kombiniranom s kompresibilnim k-omegaSSTSAS turbulentnim modelom. Rabljeni pristup bazira se na podjeli utjecaja fluktuirajućih i osrednjenih polja brzina u okviru subtenzora i modeliranju svakog od njih odgovarajućim turbulentnim viskozitetom. U proračunu, "RANS mod" se koristi u područjima strujnog polja koja se s prihvatljivom točnošću mogu tretirati kao stacionarna, npr. u graničnom sloju, dok se "LES mod" primjenjuje u dominantno nestacionarnim područjima, daleko od krila. Diskretizacija jednadžbi strujanja vrši se metodom konačnih razlika na nestrukturiranoj mreži. Metoda je verificirana na Onera M6 krilu. Paralelizacija se provodi dekomponiranjem mreže na subdomene i uporabom Open MPI tehnologije. Implementacija turbulentnog modela obavljena je uporabom OpenFOAM-a. Simulacija strujanja provedena je i u ANSYS Fluent-u, a rezultati dobiveni pomoću ove dvije metode uspoređeni su kako međusobno, tako i s Onera M6 eksperimentom. Ključne
doi:10.17559/tv-20140404130058 fatcat:illoqyqv3vb6fjrt4cjatrp3py