Assessment of time implicit discretizations for the computation of turbulent compressible flows
TypeCommunications avec actes
Restrictions on the maximum allowable time step of explicit time integration methods for direct and large eddy simulations of compressible turbulent flows at high Reynolds numbers can be very severe, because of the extremely small space steps used close to solid walls to capture tiny and elongated boundary layer structures. A way of increasing stability limits is to use implicit time integration schemes. However, the price to pay is a higher computational cost per time step, higher discretization errors and lower parallel scalability. A successful implicit time scheme for scale-resolving simulations should provide the best possible compromise between these opposite requirements. In this paper, several implicit schemes are assessed against two explicit time integration techniques, namely a standard four-stage and a six-stage optimized Runge–Kutta method, in terms of computational cost required to achieve a threshold level of accuracy. Precisely, a second-order backward scheme solved by means of matrix-free quasi-exact Newton subiterations is compared to time-accurate Runge–Kutta implicit residual smoothing (IRS) schemes. A new IRS scheme of fourth-order accuracy, based on a bilaplacian operator, is developed to improve the accuracy of the classical second-order approach. Numerical results show that the proposed IRS scheme leads to reductions in computational time by about a factor 5 for an accuracy comparable to that of the corresponding explicit Runge-Kutta scheme.
Showing items related by title, author, creator and subject.
SCIACOVELLI, Luca; CINNELLA, Paola; CONTENT, C.; GRASSO, Francesco (Cambridge University Press (CUP), 2016)A detailed numerical study of the influence of dense gas effects on the large-scale dynamics of decaying homogeneous isotropic turbulence is carried out by using the van der Waals gas model. More specifically, we focus on ...
High-order implicit residual smoothing time scheme for direct and large eddy simulations of compressible flows CINNELLA, P.; CONTENT, C. (ELSEVIER, 2016)Restrictions on the maximum allowable time step of explicit time integration methods for direct and large eddy simulations of compressible turbulent flows at high Reynolds numbers can be very severe, because of the extremely ...
BUFI, Elio Antonio; CINNELLA, Paola; MERLE, Xavier; CINNELLA, Paola (ASME, 2015)The design of an efficient organic rankine cycle (ORC) expander needs to take properly into account strong real gas effects that may occur in given ranges of operating conditions, which can also be highly variable. In this ...
Multiple-correction hybrid k -exact schemes for high-order compressible RANS-LES simulations on fully unstructured grids PONT, Grégoire; PONT, Grégoire; BRENNER, Pierre; BRENNER, Pierre; CINNELLA, Paola; CINNELLA, Paola; MAUGARS, Bruno; MAUGARS, Bruno; ROBINET, Jean-Christophe; ROBINET, Jean-Christophe (Elsevier BVElsevier BV, 2017)A Godunov's type unstructured finite volume method suitable for highly compressible turbulent scale-resolving simulations around complex geometries is constructed by using a successive correction technique. First, a family ...
SCIACOVELLI, Luca; CINNELLA, Paola (ASME, 2014)Transonic flows through axial, multi-stage, transcritical ORC turbines, are investigated by using a numerical solver including advanced multiparameter equations of state and a high-order discretization scheme. The working ...