Implementatation of Neuman boundary conditions

Dear all. I am solving naveir Stokes equations for elliptical shape bubble flow in fluid. I applied my neuman boundary conditions and I got equations in which the the Neuman BC in weak form (equation 10) as show as in figure. See the attached image. The equations has three depenedent variables (u, v, p). I wrote it in component form i. e. x and y dims. Now I do not know how can i assign three weak contibutions to the bubble surface. Please help.