Load in local coordinate system

Hello,
 
Im trying to solve cylindrical waves propagation in the air and now i am stuck with how to do the loading here. As a guideline i am using OS-1330: Acoustic Analysis of a Half Car Model, but i am not sure how to do the loading. In tutorial, it is done using unit-load, but here, i guess i need to do unit-load in local coordinate system or is it possible to define loading for nodes on the cylindrical curve as vertical to curve? Curve highlighted in red in the picture.

Thanks,

Regards

A.