Numerical investigation of flow separation from aircraft tail surfaces

The study of the flow around a vertical tail plane (VTP) in design conditions is challenging. The flow is unsteady and detaches massively from the tail surfaces. Current industrial design techniques are based on steady RANS approaches, and, for this reason, they might fail in computing the flow when separation occurs. Moreover, in design conditions, the VTP is characterized by the defection of the rudder, which allows control and balance of the aircraft. Therefore, flow separation might occur also on the rudder. However, in this case, the flow detaches because the presence of a mild pressure gradient, and it is even more difficult to compute accurately this kind oh physical conditions with current design methods. This paper addresses to the study of flow separation with hybrid RANS/LES techniques, as a follow-up of a precursor study which had shown that steady and unsteady RANS are not satisfactory for this kind offlows. Delayed Detached-Eddy Simulations (DDES) are performed on a generic aircraft tail geometry, showing a good improvement of the computedflow solution with respect to precursor studies on the same test case