How to do flow simulation for enclosure without any fan and air vents?
if you have openings in your domain, you create lids.
if your domain does not mesh that means you still have openings so you have to check the geometry to find the openings.
if the domain is fully enclosed, you select some walls as being the inlet and outlet.
2 Model Preparation 2 Create Lids - YouTube
2 Model Preparation 3 Manually Creating Lids Part - YouTube
2 Model Preparation 5 Check Geometry - YouTube
3 Creating a Simple Flow Study Fluid in a Pipe 2 Applying Boundary Conditions - YouTube
choose internal analysis
and make sure that internal cavities without flow conditions are not excluded
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