To analyze the state of airflow around ski-jumpers, a measurement technique has been developed. It is based on the surface tuft method and enables us to analyze the airflow in the taking-off of a real jumping trial. First, the distributions of the airflow orientation and its perturbation were measured along the back of the human mannequin that took the crouching position on a running car. Apparent turbulence was found at the back of the neck and behind the hip. Then, this technique was applied to the analysis of airflow in the taking-off phase of real ski-jumping. It was newly found that the airflow around the jumper started being disturbed after the jumper passed the hill edge. In the analysis of this phenomenon and the recorded posture transition of the jumper, the information useful to improve the score in competition was obtained. Through this study, the effectiveness and the usefulness of this technique for aerodynamic analysis in sports was verified.
