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12.4  Beam-Warming  Method                                            359



         where  /  is the  unity  matrix  given  by

                                            1 0  0  0
                                            0  1 0  0
                                                                         (12.4.14)
                                            0  0  1 0
                                            0  0  0  1

         and  the  Jacobian  matrices  A,  P,  R,  R x,  B,  M,  iV,  N y  are  given  in  Appendix
         12.  We  note  that  in  Eq.  (12.4.13)
                                                       M-Ny
                                              - I   B -
           dx  V      Re     Redx   J                    Re
                                                                        (12.4.15a)
         are  equivalent  to
          d_       P-R*     J_d_      7]       5        M-Ny       1  <9  \     1
              A                   R)AQ            [(-
         dx          Re     Redx"                         Re
                                                                        (12.4.15b)
         The  left-hand-side  of  Eq.  (12.4.13)  can  be  factored  and  expressed  in  the  form

                   OAt
             [I}  +                                    2   [i?]"
                  l + £                           Redx
                  9At                         n      ^  2
             [/]  +  I                            ^ 7 ^ W  n    ZiQ"
                    + £                           Re<9j/                 (12.4.16)
                      d
                At
           -{  1 + C  r - ^ M ( - ^ "
                      &
                                                 1
                 OAt  1   I^-'I      +   IW- !           £      7 1 - 1 '
              +  l  +  £Re                           +      :(zAQ
        The  solution  of Eq.  (12.4.16)  is obtained  in  two  steps
         Step  1:

                  9  At  d  ( u]  _  [P] -  [R x  1  d 2          n-1/2
            [I]             [Al                       2  [R] n   zAQ
                        die  \       Re          Re  dx
              At
                                                                         (12.4.17)
             1 + C  dx  \       Re   J     dy           Re
                6At  1   d_      1     | ^r')                  n - l i
             +  l  +  £Re dx  (Avr )  + (           +      (4Q
         Step  2:

                        5         [M]                              n        n 1 2
            M +            ARI        -  W        r>„  a„,2 ^  J  Z\Q  =  AQ ~ /
                                                       2
                                                  Redy
                                                                         (12.4.18)
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