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-   -   Helicopter rotor (http://www.cfd-online.com/Forums/fluent/35640-helicopter-rotor.html)

white February 4, 2005 05:28

Helicopter rotor
 
What is the possibility to simulate the helicopter rotor in forward flight by using Fluent 6.1? If could, can anybody give some suggestion to solve this problem. Thank you.

Luca February 4, 2005 05:53

Re: Helicopter rotor
 
Do you have to model some aeroelastic phenomena?Luca

white February 5, 2005 01:19

Re: Helicopter rotor
 
Thank you for reply. Actually, I do not have to simulate the aeroelastic phenomena, but just to obtain the blade load and flow pattern between blade.Do you have some idea?

Based on my reading, MRF, SMM and Dynamic mesh model is the appropriate technique to model the rotor at forward flight. But which one is more accurate one?

However, If you have any idea or example including tutorial to solve this problem, you can suggests it to me.

Thank you Luca, I'm really appreciate your help.

Riaan February 7, 2005 13:04

Re: Helicopter rotor
 
This is tricky...

You need to know a1s, b1s, B1,A1 and Theta (main rotor) for your helicopter blade/disk - which you could get from trim calculations.

When I did this, I used CAMRAD/JA software to get first order estimates, and then fed this data into a CFD code (Star CD, if I can remember correctly).

I worked with a guy called Kaven Naidoo, CSIR, South Africa on this problem. I did the trim calcs, and he did the CFD. I think his email is Knaidoo@csir.co.za but I may be mistaken - otherwise just go to csir.co.za and search for his name.

Riaan February 7, 2005 13:07

Re: Helicopter rotor
 
http://www.cd-adapco.com/news/20/helicopter.htm


white February 7, 2005 23:13

Re: Helicopter rotor
 
Thanks a lot Mr. Riaan.

Your advice is really meaningful to me. I'm just e-mail Mr. Kaven Naidoo and still waiting for his reply. For your information, all the trim (collective and cyclic)input have been estimated by using blade element theory. I've heard about CAMRAD and its superiority on helicopter simulation. But here we don't have that software. That why BET approach was chose.

However Mr.Riaan, If you got any tutorial or guide or any paper to simulate the helicopter rotor blade using CFD approach, you could forward it to me via this e-mail: naridhwan@gmail.com

I'm really appreciate of your help.

gelisli February 8, 2005 09:26

Re: Helicopter rotor
 
Hi,

MRF and SMM are only apropriate for hover. You can not solve forward flight using one of these model because they do not allow flapping,pitching or lead-lag motion. You can use dynamic mesh model in conjuction with a UDF that calculates the rotor dynamics based on the rotor surface loads (and centrifigual force) but it is very time consuming and not easy to implement such a code. The best possibility is to use "virtual blade model " udf. If you use this udf, you model the rotor as a disk instead of a 3d solid model. Then this udf calculates the source terms that are need to be added. However, if you use this model you can not calculate the tip vortex effects(actually it is very difficult to calculate that kind of effect because of viscous dissipation).

I hope this helps,

Regards,

white February 14, 2005 00:22

Re: Helicopter rotor
 
Thank gelisli, actually and for the first approximation, I would like to eliminate the flapping motion of the blade. However, thank a lot for your suggestion, It really meaningful to me. And if I would like to model it by using dynamic mesh, how do I use the "virtual blade model"? Could you give me some idea?

Thank


gelisli February 14, 2005 03:09

Re: Helicopter rotor
 
Hi,

If you are using virtual blade model you dont need to use dynamic mesh model because of the fact that your model does not inclued any rotor geometry. Actually, You use a disk instead of a complete 3d rotor geometry and let the virtual blade model (VBM) udf calculates all the flapping and pitching effects and apply the source terms for that disk. If you have access to www.fluentusers.com you can fin a detailed presentation about the model.

Regards,

white February 14, 2005 21:04

Re: Helicopter rotor
 
Thank you gelisli. Actually there are to many approaches to simulate the rotating blade in forward flight. However, I will try the VBM. This method looks simple than the dynamic mesh. Thank you very very much. I'm really appreciate your help. I also will remember your e-mail add. and may contact you once I got a problem. Thank you, Thank you.

gelisli February 21, 2005 07:05

Re: Helicopter rotor
 
Hi,

If you have time to solve this problem I suggest you to wait for Fluent v.6.2 because it will include built in virtual blade model udf and required GUI interface for problem setup. However, it is not easy to say when it will be available for download.

Regards,

white February 25, 2005 00:16

Re: Helicopter rotor
 
ok, thank you for the information.


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