2008 Volume 70 Issue 3 Pages 58-64
A clarification of the air drag of grains is important for investigating the winnowing mechanism. The feed rate of the threshing unit of the combine varies with the operating speed. It is essential to elucidate the relationship between the air drag of grains and feed rate.
In this study, the flight velocity of paddy grains was measured by particle image velocimetry, and the influence of the drag of grains associated with decreasing porosity was clarified. Therefore, in order to consider this influence, a correction coefficient was formulated from theoretical considerations and experiments. The terminal velocity of the grains was calculated and compared with experimental result. Then the validity of the formulated correction coefficient was verified.
