1. Astronautics, Inc., 1987. All rights resewed. 378
2. grid system with 103 points i n the x direction and 97 ooints i n the z direction. The computational' domain i s confined t o one between 176 chords upstream from the leading edge and 185 chords downstream from the t r a i l i n g edge i n the streamwise direction, and 398 chords each above and below the airf o i l i n the transverse direction (see Fig. 2a). The a i r f o i l i s represented by a s l i t , along which we assign nearly equal grid spacing with 23 grid points. Outside of the a i r f o i l s l i t , the grid spacing i n the streamwise direction i s assigned by a mild stretching according to a spacing ratio A X / A X + 1.2 - 1.4. Gradual stretching of the mesh size from the s l i t to the lateral farfield, similar t o the ZMESH assigned i n ATRAN2, i s adopted i n the transverse direction.