1. AstronauUa.Inc. 1985. Allrightsreserved. 1 11. Numerical Scheme
2. If F depends only on U it is shown in [8] that the scheme (2.1) is second-order accurate in time and fourth-order accurate in space ((2-4) scheme). Specifically, if At is the time step and Ax the space ste then 5he truncation error is o(At(()"+ (At) )). Thus the sch me is fourth
3. Although true fourth-order accuracy is obtained only for At = A AX)^) it has been found that (2.1) is considerably more efficient than second-order schemes (see for example [61, [9-101). For two-dimensional problems (2.1) can be used together with operator splitting [Ill to maintain the (2-4) accuracy. Specifically, for the eauation
4. Atypical comparison between the second and fourth-order schemes is shown in Fig. 2. The streamwise velocity is plotted against y at a location of 1.0 ft. from the leading edge (Re * 9 17174), where Re ,is the Reynolds number