# Setting new border label by modifying the former border

Dear all

I have an airfoil which I introduced as follow in FF++. now I want to specify some sluts on the airfoil and change the label. do you know how I can do that?

real CC = 0.95105651629515357211643933337938;

real SS = -0.30901699437494742410229341718282;

// Mesh

border Splus(tt=0., 1.){real t=tt^1.5;x=CCt -SS1.25*( (0.17735sqrt(t) - 0.075597t - 0.212836*(t^2) + 0.17363*(t^3) - 0.06254*(t^4)) );

``````                                                                               y=SS*t+CC*1.25*(0.17735*sqrt(t) - 0.075597*t - 0.212836*(t^2) + 0.17363*(t^3) - 0.06254*(t^4));

label=2;}       // the upper airfoil surface
``````

border Sminus(tt=1., 0.){real t=tt^1.5;x=CCt - SS1.25*(-(0.17735sqrt(t) - 0.075597t -0.212836*(t^2) + 0.17363*(t^3) - 0.06254*(t^4)));

``````                                                                               y=SS*t +CC*1.25*(-(0.17735*sqrt(t) - 0.075597*t -0.212836*(t^2) + 0.17363*(t^3) - 0.06254*(t^4)));

label=2;}
``````