Automotive CFD Mesh Generation Fatal Error

I am trying to do an initial aerodynamic simulation of my vehicle to aid in designing an wing.
When trying to generate the Mesh, I am getting “An error occured” with no further information.

Hi there,

Thanks for reaching out. Unfortunately, your geometry is incredibly dirty and therefore meshing (and solving) is going to be very laborious. You may have better luck with the hex-dominant mesher. The Standard mesher is a surface-based mesher. It starts by meshing all surfaces and then works on building out the mesh into the inner volume. I suspect there’s an error on one of the many dirty faces and that triggers the error.

The hex-dominant mesher is based on snappyhexmesh. This is a cut cell mesher and therefore can handle dirty faces better. I’ll make a copy of your project and will try a few things on my end as well. It’s worth mentioning that your time may be better spent cleaning the original CAD in your CAD tool vs. trying to make the mesher work.

I’ll update you here if I make some progress.



Hi @dlezak ,

I was able to successful mesh using the Hex-dominant mesher. Unfortunately, like I mentioned previously, my simulation diverges due to poor mesh quality. Although I can generate a mesh, the CAD still has such poor quality that it causes the mesh to have poor quality and causes divergence. You can see in my meshing log the max volume ratio is ~135.

Acceptable range: 0 to 100
	min: 1
	max: 135.34144565614062
	average: 1.5260599750032888
	standard deviation 1.843523294604037
	median: 1.0029300478616578
		99.9-th percentile: 19.213661542197677
		99.99-th percentile: 38.670931807472925
		99.999-th percentile: 71.01105728002392

Below are some isovolumes showing areas with a volume ratio of over 90:

Here’s a link to my version of your project. I recommend cleaning up the CAD and defeaturing: remove antenna, door handles, logos, mufflers, tire tread and lug nuts, windshield wiper spray nozzles, etc.

Best regards,
Matt Bemis

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