Unstrucutred Suface for one inlet within a structured mesh
 

Hello,

I have a structured mesh for a nozzle which i have generated a structured mesh for. however i need a concentric separate inlet (30mm diameter) for an ethanol inlet within the other inlet and this inlet is 0.5mm in diameter (which i only need for a DPM Injection so ). trying to maintain a fully structured mesh ruins the overall quality of my mesh as the two concentric circles are so widely variant. So what I am trying to do is on the sufrace just generate an unstructured mesh for that surface and leave everythin else alone. how can i go about doing this? I have added a picture to make a little clearer

You can create a good structure mesh for both the inlets by using blocking.