격자를 이용한 와류진동 평가용 낮은 난류강도의 바람 생성

Wind turbulences can be generated in a wind tunnel by two different ways, i.e., a passive method using a grid and an active method using a turbulence generator. The grid-generated turbulences have been conveniently utilized in many cases by simulating various levels of turbulence intensities. The dominant factors affecting the generated turbulence intensities shall be the size of grid elements, gap distance between elements and the distance from the grid to the testing point. The effect of these three factors was estimated for a single grid element at the beginning. It is confirmed that the turbulence intensity increased as the size of grid element increased. The turbulence intensity also increased as the gap distance between grid elements as well as the distance between the grid and the testing point decreased. The homogeneity of the turbulence intensity was also confirmed for the cross-section of the wind tunnel up to 350mm width from the center of the 1m-wide wind tunnel. The 2.5% level of turbulence intensity was successfully realized with the grid for the purpose of the evaluation of vortex-induced vibration of bridge decks. The observations during the development of such a low-level turbulence intensity are discussed.