Experimental study for wind velocity profiles in and around a rice canopy at different growing stages

Vertical profiles of wind velocity in and around a rice canopy at three different growing stages were experimentally investigated using a wind tunnel. The vertical profiles were measured between rows of rice bunches and above bunches in a rice canopy, and between rows and behind bunches outside the canopy. Each vertical profile was compared with the input profile of wind velocity, and trends in attenuation and acceleration of wind were examined. It was found that wind was accelerated above rice bunches, and the extent of acceleration depended on a growing stage of rice. For vertical profiles between rows of rice bunches, attenuation of wind velocity was found at the area that the rice bunches spread out leaves between rows, and wind was accelerated above and below the area. A peak location of attenuation behind bunches changed depending on a growing stage. For locations below appearance height of a rice canopy, the peak of attenuation appeared right behind the rice bunch 8. The wind velocity decreased by 60 % at the growing stage 2nd and 3rd. For locations above appearance height of a rice canopy, acceleration was prominent at the 3rd growing stage, and the wind velocity increased by 60%.