I have done my CAD model as surfaces in Onshape. How can I connect all the individual surfaces together to form one part so that I can perform CFD on it? Thanks for your help
Well, to get the geometry for CFD analysis, you need a “closed shape” in your CAD. As far as my experience shows, any time you close a volume with surfaces in Onshape it will create a solid Part.
You simply upload this part to SimScale and use as a flow domain / flow obstacle in your simulation.
In case of trouble do share the link to example geometry in Onshape so we all can take a look and help
Actually you don’t have to have fully closed and sealed geometry. All depends on what you do.
Here I did simple meshing test where I presented the general idea (I used surface model):
As you can see it’s all about the gap and mesh element sizes. However, as @psosnowski wrote, it’s highly recommended to have solid geometry (!). Otherwise you ask for trouble