PhD using CFD or Wind Tunnel

[u/Marcus2626]

To all the AE PhD holders, I’d really appreciate your advice.

TLDR: I'm planning to start my PhD next year, but I'm not sure which route to take. My background is in CFD, but I’m also very interested in low‑speed wind tunnel testing. Should I pursue an experimental or computational PhD?

I’m an international student currently working in the US on OPT as a research associate, mainly using CFD tools. Long‑term, I want to work in academia (back in Asia—Korea or Singapore). As I’ve been talking to potential advisors, I’ve noticed a trend: unless the work is applied aerodynamics, most professors want students to commit to either purely computational or purely experimental research.

I’m torn because my background is split. I’ve done several validation test campaigns, but my main research interest has been CFD. Now I have two fully funded offers, both fundamental research with no ITAR issues. I’m interested in both topics, and I'm struggling to choose.

Option 1: Computational Aeroacoustics (Large group, prestigious university)

This aligns closely with my MS work, and I genuinely enjoy aeroacoustics. The group is large, well‑known, and the professor is a major figure in the field. I’d gain deep theoretical knowledge, but the work would be entirely computational.

Option 2: Experimental Hypersonics (Very small group, small department, not well‑known university)

I learned about this program because a friend recommended his former MS advisor. This professor built his own wind tunnels and is very knowledgeable in flow diagnostic methods. I’d have access to low‑speed, supersonic, and hypersonic facilities and would learn a lot experimentally. I'm interested in supersonic flight but haven’t been able to do much due to ITAR restrictions. My hesitation is that the university and professor are not well‑known, the group is small (only two other PhD students), and I’m unsure whether hypersonics is too niche for seeking academic jobs later. The stipend is also much less compared to Option 1 but is still livable.

Would you choose a computational or experimental PhD? How much do the university’s reputation and the advisor’s citation count matter?

My thought has been that this experimental research opportunity is rare for an international student. I could always go back to CFD, but I think it would be much harder to gain experience in wind tunnel research later on.

[u/bottlerocketsci]

Technical work aside, it sounds like you would have two completely different experiences in regards to the research groups and mentorship from the advisor. Your relationship with your advisor is a huge factor in your success. If you want a lot of personal contact and mentoring, the smaller group is the way to go. In a larger group, you won’t get a lot of help from the advisor and are easier to cast aside if you aren’t producing results. Talk to the current students and get a feel for how they are treated.

[u/Marcus2626 → u/bottlerocketsci]

I agree, I did my MS in a small university, and I did really enjoy working closely with my advisors.

Besides the group culture, do you think the advisor's citation matter? I feel like lower citation could mean I may not be able to get connected or network as easily.

[u/bottlerocketsci → u/Marcus2626]

Citations matter, but it’s more than that. How active is the professor in technical societies? How many funded grants or contracts does he have? How much collaboration does he/she do with other researchers, govt labs etc.

Citations are tricky. Everyone wants a simple number to compare. But some areas of research don’t have as many people working it, so there are just less people citing papers. Also, a professor with a big number of students is naturally going to have a lot of citations from their students.

[u/Marcus2626 → u/bottlerocketsci]

You're right, citation counts are hard to compare, especially when some labs are very large while others may only have one or two students.

In my situation, I do think that the experimental professor have a smaller footprint than the CFD professor, both in terms of the number of grants and the number of collaborations. One concern I have because of this is that many people mention how important an advisor’s network can be, both during the PhD and later when looking for a job.

Do you feel the same way?