code_saturne User's Forum

To calculate moment you need the cross product of the force vector and distance vector. Distance vector (assuming you rotate about origin) is stored in cdgfbo array. Just search for it in usproj it is explained well. From this you can calculate the moment at each individual face and then sum the moments as you do now with forces to get the complete moment.

THanks James,

I have a question concerning the number the tourns of the turbine,

Normally if I want that the turbine make 5 tourns/seconde I put in the subroutine usini1 but I obtiened a great velocity!

Do you have an idea about the number need to "omegay" to obtiened a correct velocity

Hi - I think you've asked this one before (in any case I have answered it) so try using the forum search feature.

Hi James ,

I find your explanation for "omegay" :

http://code-saturne.org/forum/viewtopic ... a&start=50

So, according to your explanation, if I put "omegay=2*pi" -ie. the turbine make 1 tourn /s

and in my case I want that turbine make 5 tourns/seconde, so I put "omegay = 2*pi*5.d0" in results I get a high velocity that's no correct, normaly with (5 tourns/seconde) I need to get a velocity maximum equal to about 1.5 m/s !! but me I obtiened Umax = 58.6 that's not correct!

What is the radius of your turbine blade?

What is your inflow velocity?

THe radius of the turbine in this case is 4.75 cm


I don't impose the velocity in the inlet since I'm running the fluid through the turbine

if I use this relation "omega = u/radius = 1.5 / 0.0475) I obteined omega = 31 per seconde -ie = 2*pi*5 (that's correct) so if I put in USINI1 "omegay= 31.d0 I obtiened Umax = 58

So looks like you are defining omegay correctly.

It is probably another problem.. does the listing reveal anything?

No, the listing reveal nothing

here is the listing, normaly no prob

You have only performed 10 iterations so you should perform more.

And if you are using 5 revs per second then you need to decrease the time-step. But it's hard to know since this listing doesn't correspond to your questions (omegay=0.5 here, and the domain is massive compared to your radius of 0.0475m).

Is this the correct listing?