1990 Volume 34 Pages 229-234
Experimental investigatins on the fluid forces acting on two circuler cylinders in tandem arrangement were carried out. The Reynolds number and the distance between the cylinders were varied in the range 1×104<Re<8×104 and 1≤1/d≤6. As a results of systematic investigation on drag and lift forces measured at the same time, fluctuation of fluid forces are divided into four patterns according to their charactristics. It was found that the intermittent changes of time-mean drag and intensity of fluctuating drag and lift occure in the range 1/d=3-4 at front cylinder and 1/d=2.5-4 at rear. This discotinuous changes of fluid forces is caused by the abrupt change from one stable flow pattern to another. The results were summarized in several figures from which one can obtain the timemean and the intensity of fluctuating drag and lift and the Strouhal number.
