Numerical Schemes and Hybrid Approach for the Simulation of Unsteady Turbulent Flows

The paper presents a brief review of computational approaches for the simulation of turbulent flows and shows that the correct calculation of large-scale vortex structures necessarily requires the use of eddy-resolving methods, while the applied numerical schemes must be stable and accurately describe the spatial evolution of vortices. The dissipative properties and stability of most numerical schemes implemented in the OpenFOAM package are analyzed by solving problems on the decay of the homogeneous isotropic turbulence and scalar transfer. It is established that the considered schemes are not suitable for correctly calculating the propagation and dissipation of vortices in space; therefore, they are refined to eliminate oscillations and maintain an acceptable level of dissipation. An algorithm for combining the URANS and LES methods using zoning of the computational domain is described and implemented. To test the implemented calculation method of unsteady turbulent flows, we simulate the flow around a maneuvering aircraft with an installed airbrake deflection. The flow patterns of the aircraft and its aerodynamic characteristics are obtained and compared with the experimental data.