AN APPROXIMATE METHOD FOR THE DRAGS OF 2-DIMENSIONAL OBSTACLES AT LOWREYNOLDS-NUMBERS

We propose a new simple method of computing the drag coefficients of t wo-dimensional obstacles symmetrical to the main-pow axis at Reynolds numbers less than 100. The governing equations employed in this method are the modified Oseen's linearized equation of motion and continuity equation, and the computation is based on a discrete singularity meth od. As examples, simple obstacles such as circular cylinders, rectangu lar prisms, and symmetrical Zhukovskii aerofoils are considered And it was confirmed that the computed drags agree well with experimental va lues. Besides optimum shapes of these geometries, which minimize the d rag coefficients, are also determined at each Reynolds number.