Abstract
The flow pattern across tube banks in the low Reynolds number region was obtained by means of the finite element method. The variation of flow pattern with pitch ratio and arrangement of tube banks was deduced from the local surface vorticity distribution. The frictional drag coefficient for the first row in a tube bank was almost identical with the case of a single row of cylinders, regardless of arrangement, and was dominated by the flow where minimum spacing exists between adjacent cylinders in the direction perpendicular to the flow. The frictional drag coefficient for the inner row of the staggered configuration was higher than that for the first row due to the impingement of jet flow formed at the preceding row, while that for the inner row of the in-line configuration was lower than that for the first row due to the vortex formed at the gap between adjacent cylinders in the flow direction. This tendency depended on Reynolds number and pitch ratio.
