Attempting to use flow simulation to model a rotorcraft configuration with one main rotor and two forward facing propellers. I am able to define rotating regions (81 and 65 rad/s for the rotor and propellers, respectively) but for some reason the propellers won't actually rotate. Completely out of options now - is someone able to have a go? Thanks, in advance!
Hello,,
For what I've seen : your rotating region for the propellers was not correctly set ; it must enclose only what will be rotate, so not the wings. Here a screen of what it should look like :
The problem will be the remaining part of the propeller : it seems it's tangent to the wing above, a rotating region won't work properly if you try something with this geometry. Maybe try to just move the wing a bit above to avoid the contact of the wing and the propeller. Then, you can apply a moving wall with an angular speed which is the same as you defined in the rotating region. Make sure all the surfaces which are supposed to moved, are selected for this boundary condition.
Hope it'll help.
Hi,
Thanks for your response - I followed your advice and moved the propellers downwards, and defined them as walls with an angular speed. However, it appears to have not worked. Any chance you can have a go or offer some alternative advice - I have attached the updated file. Kind Regards!
Hi,
I think I was not enough clear, sorry : you have to apply the boundary wall condition on the surfaces which have axis-symmetry, so these in blue :
I'll try it and let you know if it works. I'll also move a bit the rotating region of the helix to avoid the the proximity with the wing (in red).
So, to sum up, you will have :
- 1 rotating region for the rotor
- 2 rotating regions for the propellers
- A group of walls with angular velocity at the same speed as the propellers
And one last thing : you have to make sure the direction of the reference axis is well defined so the it's pointed to the axis of the axial symmetry :
Thanks again for your help, though still doesn't appear to be working. Updated file attached again, thanks!
So,, I've managed to make it works : but the thing is that (maybe) you cannot see properly the propellers rotating because of the high velocity of the flow coming from the front which is higher than the max tangential velocity of the propellers (the V = R*omega). The screen above shows the simulation with a front velocity of 10 m/s instead of the 74 m/s before.
That seems to work, thanks so much for your help!
Hello,,
For what I've seen : your rotating region for the propellers was not correctly set ; it must enclose only what will be rotate, so not the wings. Here a screen of what it should look like :
The problem will be the remaining part of the propeller : it seems it's tangent to the wing above, a rotating region won't work properly if you try something with this geometry. Maybe try to just move the wing a bit above to avoid the contact of the wing and the propeller. Then, you can apply a moving wall with an angular speed which is the same as you defined in the rotating region. Make sure all the surfaces which are supposed to moved, are selected for this boundary condition.
Hope it'll help.