Measurement of turbulent flow characteristics of a rectangular duct with a 180.deg. bend by hot wire anemometer

열선유속계에 의한 180.deg.곡관을 갖는 직사각 단면덕트에서의 난류유동 특성의 측정

Velocities and Reynolds stresses in 3-dimensional turbulent flow in rectangular ducts with a 180.deg. bend were measured by hot wire anemometer. Slant wire was rotated to 4 directions and I type wire was rotated to 2 directions and the voltage outputs of them were combined to obtain the mean velocities and Reynolds stresses. Flow characteristics in the 1.5:1 and 2:1 cross secioned 180.deg. bend were measured and the results were compared with the data from Moon for the square sectioned 180.deg. bend flow. Flows in rectangular sectioned 180.deg. bend show the reduction in secondary flow and therefore the reduction of double maximum in local mean velocities.

본 연구에서는 문등이 제안한 방법에 의하여 직사각형 단면의 180˚곡관유동 에서 속도분포와 난류성분을 측정하여 단면의 종횡비 변화에 따른 유동특성과 난류특 성의 변화를 고찰하였다.