Infinity Boundary Conditions
Far away from the body (toward infinity), in all directions, the flow approaches the uniform freestream conditions. Let be aligned with the x direction as shown in Figure 3.18. Hence, at infinity,
З Ф дф
и = — = — = Lx дх 3 у
Boundary conditions at infinity and on a body; inviscid flow.
дф дф ду дх
Equations (3.47a and b) are the boundary conditions on velocity at infinity. They apply at an infinite distance from the body in all directions, above and below, and to the left and right of the body, as indicated in Figure 3.18.