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Rui May 4, 2007 15:36

PhD using CFX
 
Hi all,

I'm thinking about doing a PhD in CFD.

I'd like to do some work related to physical and numerical modelling. I suppose I could, for example, build a code with a new numerical model. But I think it would be much more interesting to do it using CFX, (this is, to implement something in CFX) giving you a background on theory but also giving you the chance to become an expert (I think) in CFX, what could be very good for a future job.

I worked with CFX for 2.5 years and I did my Master thesis based on work done with CFX, so I already have some experience with the software, but actually I don't know what's possible to do in CFX regarding numerical modelling. I know it's possible to create user functions and Pearl and Fortran scripts, but I never needed to go further than CEL.

So, here go my questions: What work do you think could be done in CFX which could lead to a PhD? Would it be possible to implement in a new turbulence or combustion model, or discretization scheme, or is the code that closed to this kind of interventions? I know Glenn did his PhD working with CFX (I've downloaded his thesis from his university site), but he did it with CFX-4. Is the current version of CFX, or Ansys CFX as it's called now, more closed to the implementation of subroutines? Do you know more cases of people who have done their PhD using CFX? Suggestions are welcome.

Thanks,

Rui


Glenn Horrocks May 6, 2007 19:28

Re: PhD using CFX
 
Hi,

Yes, I did my PhD in CFX, but my work was on developing engine technology, not writing new models into CFX. I only wrote stuff necessary to get CFX4 to model IC engines.

A PhD is a "contribution to knowledge". All your comments assume that your contribution will be in the form of improved CFD software. Don't forget that an equally valid form of contribution is to use existing software (such as CFX) to invent or understand fluid processes. In this case your contribution could be a new engine technology, a new valve design or an improved fan design - or whatever you are looking at.

It depends whether you want to do a PhD in numerics or a PhD in an application. That's your choice.

Glenn Horrocks

Rui May 8, 2007 13:51

Re: PhD using CFX
 
Hi,

Thanks for your answer, Glenn.

As part of my PhD I'd like numerics to play an important role, but actually I wouldn't like to stick only to numerics, I'd like to have an application or application field in mind.

As I said in my previous post, I'd prefer to work with existing commercial software than creating my own code. And this for a few reasons:being an expert in CFX, for example, could be very valuable for a future job;I think working with physical and numerical models is interesting, but debugging a code is not;and in my opinion the time you loose writing, and debugging, a code, could be used in more interesting tasks.

I understand that you could use existing CFD software to improve a new technology. But I also understand that there are people doing this using the software almost as a black box. I don't want to devalue all these people, as, for instance, there are experimentalists who use numerical simulation software as an extra tool. But I'd like to do something where it would be necessary to understand the physics of the process and the numerics of the simulation, and not use the software as a black box and simulate hundreds of variations of a geometry.

With the questions I posed on my previous post, I intended to get an idea of what's possible to do in CFX regarding creating/improving numerical models. Apparently very little.

And I'd like to keep a question from my previous post: Do you know more cases of people who have done their PhD using CFX?

Thanks,

Rui


Glenn Horrocks May 8, 2007 18:30

Re: PhD using CFX
 
Hi,

CFX has had a huge amount of work done on it over decades by a lot of very highly skilled people. Being realistic, it is unlikely a single PhD project will significantly improve the software except maybe in a specialised area.

My PhD supervisor has done many PhD projects using CFX and other CFD codes. So yes, I know of some people who have used CFX for their PhD.

Regards, Glenn

Rui May 9, 2007 13:26

Re: PhD using CFX
 
Hi,

Thanks for your opinions, Glenn.

But my problem is that if I discuss with my Master degree supervisor (who knows a lot of CFD theory but a little about CFX), he will come up some ideas, but he doesn't know what can and cannot be done with CFX. But, probably, I should speak with him first

Rui

S. May 13, 2007 00:24

Re: PhD using CFX
 
I did my PhD using CFX. CFX is not quite the "black box" as you describe. A deep understand of CFD must be known in order to use and understand commercial codes. Garbage in equals garbage out.

Rui May 14, 2007 08:25

Re: PhD using CFX
 
Thanks a lot for your answer.

Could you please describe succinctly what kind of work you did with CFX for your PhD?

I've already worked with CFX, and I'm not complaining about it, it is a great software, but in some points I think it is a "black box".

Rui


Song May 24, 2007 22:06

Re: PhD using CFX
 
Hello, I'm a chinese student. I have used CFX to simulate the characteristics of various valve. for me, CFX is a just a black box, I agree.

However, the emphasis is not here. I saw your post carefuly, on one hand, you're interested in CFD, you want to do a great contribution to it, on another hand, you think debugging code is not interesting, and you want strengthen your CFX skills to find a good job when you graduate. Don't you think they are incompatible?

In China, there is an adage. You can't get the fish and palm of bear at the same time. Actually, lots of candidates of PhD are as confused as you including me. Maybe, in the morning, you become interested in theory research, but afternoon, you will fall into love to applicaiton. Sorry, in fact theory and application can't be splited so easily and obviously.

Anyway, my opinion is: if you'd like to do some basic research, don't use CFX, from the first step, write codes by yourselfe. Otherwise, use CFX to do some real projects, explain them in CFX......

In on word, don't expect do a great contribution in theory by using commercial package.

All answer are in your own head, which way would you like!


Rui May 25, 2007 13:40

Re: PhD using CFX
 
Hi Song,

Thanks a lot for your post.

I think I have moved my mind towards CFD application rather than pure theory. As S. said "A deep understand of CFD must be known in order to use and understand commercial codes. Garbage in equals garbage out" And I belive that depending of your interests, you may conduct your research more for a theoretical or a pratical area.

Song, are you doing a PhD in China, or are you a PhD candidate? Which university in China? Do you know some universities over there that use CFX?

I'm asking this, because I'm considering (at least thinking about) doing a PhD, or part of it, in China. I posted these 2 topics in the Main Forum: http://www.cfd-online.com/Forum/main...cgi?read=51504 http://www.cfd-online.com/Forum/main.cgi?read=52651

I'm Portuguese and I can apply for fundings to do a PhD, or part of it, outside Portugal. But I don't know how they would react to an application to a Chinese university. And you need to send lots of papers about the supervisor, the institution, the working plan, etc, etc ... what would certainly be hard to obtain being here in Portugal But the option of doing part of it here in a Portuguese university and spending some time at a Chinese university would be great

Song May 28, 2007 05:59

Re: PhD using CFX
 
Hi Rui, I saw what you post, also with others' reply. do you think they are help? I don't know, I believe,for anyone who have no experience of studying or living in China, they're so confused. Someone say good, and someone say bad. here, I don't want to state my point, but if you really need help, contact me. I'll do my best to help you. songxguan@hotmail.com


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