Methods and Strategies for the Detection and Management of Grid Induced Uncertainties in Numerical Aerodynamics

For the numerical simulation of complex aircraft configurations discretisation errors around wings and tailplanes as well as in their wakes are a key source of computational uncertainties. Both simplifications and uncertainties in the geometry description as well as improper numerical grids have an influence on the prediction of lift and drag coefficients, whereas the error magins are not well known. For this reason, the Institute of Fluid Mechanics systematically analysed and quantified grid induced uncertainties in the frame of the projekt MUNA. Based on this, strategies and tools have been developed for error detection and improvement of improperly discretised grid regions. For the detection of dicrestization errors, a method based on the artificial dissipation of central schemes has been developed. Furthermore, two methods have been developed for local grid improvement which follow two different grid manipulation strategies. These strategies are the local deformation of grids and the local refinement of hexahedra. The developed methods and tools have been verified on different test cases.