The numerical procedure for the Navier-Stokes equations developed earlier has been modified to investigate the viscous flow past a circular are at various positions and Re. Among the major new and improved features are the asymptotic expansion near the tip singularity that takes account of the are curvature to enlarge the region of its validity and the exit boundary condition that utilizes the Oseen solution to keep the computational domain as small as possible. The details of the flow field, i.e., vorticity, drag, eddy structure, etc., about the semi-circular are are presented for various Re and angles of incidence. Computations are also performed for arcs of other central angles at incidences of 0 degrees and 90 degrees. (C) 1999 The Japan Society of Fluid Mechanics and Elsevier Science B.V. All rights reserved.