Hello, I want to compute <p’*p’>, where p’ = p-
, (<> denotes time-averaged operator). I used the following expression in tav plugin, but the result of fun-avg-up is zero. Is it right? could someone give me some tips?
avg-p = p
fun-avg-up = (p-%(avg-p)s)* (p-%(avg-p)s)
Also compute the average of p^2 as avg-p2 = p*p. Then expand out your expression for \langle \tilde{p}^2 \rangle and simplify using the linearity of expectation.
Regards, Freddie.
So expend the equation <(p-avg_p)^2>, we can get <(p-avg_p)^2>= (avg-p2) - (avg-p)^2. Am I right? But the result of
is wrong. I’m not sure if I miscalculated.
Let \tilde{p} = p - \bar{p}. Then \langle \tilde{p}^2 \rangle = \langle p^2 \rangle - 2\langle p\bar{p}\rangle + \langle \bar{p}\rangle^2 = \langle p^2 \rangle - \bar{p}^2 = \langle p^2 \rangle - \langle p \rangle^2 since \bar{p} = \langle p \rangle and \langle \bar{p} \rangle = \bar{p}.
Regards, Freddie.
Thanks.
I used the FWH euqtion to compute benchmark noise problem, but the results don’t match up with the literature. And the pressure perbutation and pressure contour is attached below. The pressure perbutation is the ‘mag’ value in the fwh.csv.
The case setup is also attached, could someone give me some advice?
https://drive.google.com/drive/folders/1BHkLE9Az2keVofqyWME1jnpJeN14gVCg?usp=drive_link
@fdw Does FWH plug work? Could someone give me some advice?
Some normalization issues with the plugin were fixed a few months ago, but beyond that it is working.
Regards, Freddie.
Thanks a lot.
I used the latest plugin, but the result didn’t still match up with the literature. As in the previous pressure diagram, P’ is the mag value in the fwh file, and the angle of cosine and sin is arctan (x/y), where x and y are the coordinates of the corresponding observation point.
Can you help me check what’s wrong with this benkmark case?
Is your simulation grid/polynomial order converged?
Regards, Freddie.
The residual data is above 100 and oscillates back and forth, can this be considered convergence?
Have you run the simulation on two different grids and confirmed that the results are the same?
Regards, Freddie.
Yes, I have tried this operater, the results are same.
Do the forces on the cylinders agree with reference data?
Regards, Freddie.
Sorry for replying so late. Yes, I simulated the airfoil case again, the pressure on the airfoil wall matches well with reference data. But the pressure perbutation didn’t match up with reference.
