Cluster or workstations for turbomachinery CFD?
 

Hello all,

Need some advice.

I currently use CFD for turbomachinery, with models little more than half a million cells (one blade passage steady state) and the solution converges in about 3 hours (2000 sweeps) on a 6 core PC. I am about to use several full geometry model with about 10 million cells for both steady and unsteady computation. I am sure that I need additional computational resources.
I am planning to expand the computational resources so that I would be able to see the solution within 12 hrs.
I am confused what to get, single or several high end PC/work station or a small cluster??

1. which would be suitable for my case?
2. which would be better on a longer run for lesser CFD turn around times?
3. which is more advantageous in terms of maintenance, flexibility and cost effectiveness?

Kindly share your expertise

Kind Regards,
K

For your case, you might go for a small cluster or several workstations. A single PC will not give you enough power to reach your desired turnaround times (just a guess).

The full case has about 20 times more cells and you've got 4 times more time until you want to get the results. That means, you need at least 5 times the computing power. Maybe even more due to the worse scaling on high CPU counts.

A small cluster with infiniband interconnect will give you a better performance compared to several workstations. That could be interesting for the unsteady cases since the usually run for a long time. But cluster hardware is pretty expensive, you need a good cooling and an upgrade is usually too complicated.

Several workstations are more flexible in terms of flexibility, mainenance and I guess also cost effectiveness.

The cheapest way and the most flexible in terms of hardware upgrade etc. are several PC's, but for the cost of the lowest performance. But maybe you can purchase much more PC's for the price of the small cluster or the workstations, so you can run 2 cases at a time...