Page 140 -
P. 140

123




















          Figure 4. Sketch of the uniform flow (speed = 1, Mach number >1) past the aerofoil


                  everywhere.)  The non-dimensional  version of the  physical  configuration is
          shown in figure 4. Finally, the boundary conditions are



          and


          where the first, (3.23), ensures that, upstream, we have only the given uniform flow
                 with       and the second, (3.24), states that the surface of the aerofoil is
          a streamline of the flow.
            Equation (3.22),  with  and       is predominantly a wave equation (but
          here expressed in spatial variables, x and y); the form of this equation suggests that we
          seek an asymptotic solution





          and then we obtain







          and so on.  Correspondingly, the boundary conditions give




          and
   135   136   137   138   139   140   141   142   143   144   145