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-   -   [Need Help]calculate a helicopter rotor in forward flight (https://www.cfd-online.com/Forums/cfx/104147-need-help-calculate-helicopter-rotor-forward-flight.html)

 toil July 3, 2012 22:17

[Need Help]calculate a helicopter rotor in forward flight

Hi, all;
I have some problem in simulating helicopter rotor in forward flight. I need some help here.
the helicopter rotor in forward flight is a real difficult problem. A hovering or axis flight rotor can be easily solved by using stationary domain and rotating domain. but a rotor in forward flight is a unsteady process, and the rotor blade motion must be considered!
my problem is:
How to simulate a rotor blade while it's rotating and flapping?
What kind of moving mesh we used here?
Dose anyone did something like this before?

 ghorrocks July 4, 2012 07:30

It the rotor is simply rotating then the forward motion can be modelled by applying a velocity at the inlet and putting the rotor in a rotating frame of reference. All the different RFR models are appropriate - Frozen rotor quick, simple analysis and transient rotor stator for full transient analysis and everything in between.

If the blades are flexing (twisting, bending) then this is far more complex. I would consider a frozen rotor approach to model various blade positions and conditions and build up a library of blade performance.

But really you need to think about exactly what you are trying to get out of the analysis. Often the system can be simplified so a full transient FSI simulation is not required, but a simpler model be done which approximates the system adequately.

 kure87 November 8, 2012 06:13

I think itīs now a transient analysis, because helicopter blades in the foward flight is loaded unsymetrically.

I think for this type of problem i will split it into two domains, one domain is outer world with some direction and speed of the flow (rotor AoA for horizontal level flight must be preserved) and inside this domain is rotating domain with blades. For corect analysis may be necesary use complete rotor not only one blade. Outer domain is necesarry because flow must be stabilized before outlet.

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