Dear Fluentusers, I'd like to model an aircraft in a "frozen" steady manouver (roll or pitch for example). How to to that in FLuent ? trough a SRF? Thanks. Luca

you could create a mesh for each angle of attack (pitch) or angle of roll (roll, hahaha) and to simulate them as a separated cases, then you are able to get Cl .vs betha, Cd .vs betha, Cm .vs betha , etc.

other aproach could be to model the all maneuver using the fluent's deformming mesh scheme and UDF to give the aircraft's movement.

Pablo

dear user this is my problem too,can u tell me ,how to set deforming mesh scheme,is there any seting for that in fluent? hanry

Aerodynamic forces do not depend on the angle of roll. I need to simulate a roll angular velocity instead. Luca

For a constant angular velocity, how about using the SRF (single rotating frame)? Treat it like a large fan/propellor/turbine blade?

Good luck, Jason

Exact!! that's what I'm doing. I just needed a confirm. Thanks Luca

Well, I'd still be careful... it was a thought... you should be able to double check by looking at Vtheta just upstream of the wings... make sure one wing is at an effective positive angle of attack and the other is at a negative.

Nothing jumps out about the SRF to say that this won't work, but you'll have to so some digging into the final solution to make sure all is right with the world

Good luck, Jason

Thank you Jason. I tried to model a pitching wing (half model with a symmetry bc) and it seems to work. I get a lift increase as excpected. I also had a look at the pathlines and it's reasonable. I'll investigate a little more. Thanks Luca

Was that just a test case, or are you planning on sticking with symmetry? Just be careful... for slow rotation rates, and for bodies away from the symmetry BC this should be a reasonable assumption, but if you rotate too fast, you'll start seeing some interaction with the symmetry BC, and that can throw off your results.

I'm sure you're keeping all of this in mind, but just in case...

Best of luck, Jason

No, it was just a first simple case on a small grid to see it was OK to use the SRF. I'll have then a grid on a complete aircraft to see the roll and yaw contributions. Are you Jason from the BAE? Luca