The permanent increase and improvement of computer performance as well as of calculation codes create a developing demand of advanced and more complex optimisation possibilities already during the design process. Earlier solvers, based on the Euler-equations, were not in the position to predict viscous effects like separation. This forced the investigated flow problems to be simple. With the introduction of the Navier-Stokes equations it became feasible to predict viscous effects. This is under investigation on the example of a missile in manoeuvring flight. This state is characterised by transonic speeds and high angles of attack and roll. The resulting separation zones are still a challenge for the available codes. To tackle this problem, the working group AG42 was founded in 2004 within the “Group of Aeronautical Research and Technology in Europe” (GARTEUR). This group was provided with a validated wind tunnel experiment as basis for a qualified comparison between different codes of different research groups within Europe.
AG42 encompasses two tasks. Task 1 comprises the validation of the RANS-codes (“Reynolds-averaged-Navier-Stokes”-codes) of the contributing partners. For RANS-modelling the flow parameters are split into an averaged and a fluctuating part. The averaged part is being calculated and the fluctuating part is parameterised by the turbulence model that is part of the code. In Task 1 a missile is investigated with an angle of attack of 0<?<20°, a roll angle of 22.5° and a Mach number of 0.8. From the validated experiment surface pressure measurements along the body, force measurements of the full configuration as well as of the single fins at the rears of the body are available. All numerical simulations within this task are conducted on two kinds of grids, according to the applied solver, on a structured or unstructured grid. Within the frame of the partners’ agreement the DLR provided the unstructured grid for the other partners. Task 2 encompasses the calculation of a missile without any control surfaces under a high angle of attack of 45° by means of the so-called “Detached Eddy Simulation” DES. Here, the flow, or the grid, is split into different areas and according to a certain threshold value the equations are either solved according to the RANS-method or with a simulation method which resolves large eddies and models the small ones (LES-method, “Large-Eddy-Simulation”).
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