0 a a L FIGURE P4-13 -13. Flow straighteners consist of arrays of narrow ducts placed in a flow to remove swirl and other transverse (secondary) velocitics. Onc element can be idealized as a square box with thin sides as in Fig. P4-13. Using laminar flat-plate theory, derive a formula for the pressure drop Ap across an N X N bundle of such boxes. 1-14. Develop a numerical solution for the Blasius equation with wall suction or blowing, for a particular value *0, and compare your results with Fig. 4-15. 4-15. Derive a relation for skin-friction coefficient C, as a function of local Reynolds number Re, for boundary-layer flow toward a point sink, Eq. (4-89). Compare your result with the Falkner-Skan relations. 4-16. Develop a numerical solution for a laminar mixing layer between parallel streams, for a particular value of k, and compare with Fig. 4-17. 4-17. Air at 20C and 1 atm issues from a narrow slot and forms a two-dimensional