An invariant variational problem of the laminar boundary layer

A variational problem on minimizing, by normal injection into a laminar boundary layer, the Newtonian drag of a blunt cylindrical body in a supersonic flow of an ideal gas is considered, taking into account the limitation on the power of the system to control the injection. Using the first integral obtained, the order of the conjugate system is reduced, which enables an effective algorithm to be constructed for finding the optimal control using the grid method. The results of a computational experiment are presented, according to which the gains in the values of the drag functional for the optimal controls obtained reach 65% compared with a uniform injection law.