Ski-Jumping Aerodynamics: Model-Experiments and CFD-Simulations

The importance of the predominant performance factors from the aerodynamic point of view, i.e. — besides the jumpers’ weight — the position and posture during all phases of the inrun/flight, has been highlighted in the previous chapters. Here, the aerodynamic behaviour of a scaled down by 1: \( \sqrt 2 \) model ski jumper is investigated experimentally at full scale Reynolds numbers as well as computationally, applying a standard RANS code. Particular focus is put on the influence of different postures on aerodynamic forces in a wide range of angles of attack with a high density of measurements, i.e., small angle increments from one posture to the next. The wind tunnel results form a fine grid of data which can be used for detailed studies on flight style and aerodynamic equipments optimization. The comparison of CFD results with the experiments reveals poor agreement. The studies clearly show simulation potentials and limits in contrast to the required accuracy of the predictions. Winning or loosing in ski jumping can be a question of a few percent difference in lift or drag; common turbulence models, however, do not provide results with an accuracy as required for analysis in top level ski jumping.