A small query in Incompact3d's schemes.f90

[yzl429]

Dear incompact3d developers,
I have a question for you, in the subroutines of schemes.f90 first_derivative, second_derivative have ff, fc, fb, sf, sc, sb, sfp respectively, and also at the end of the call to the prepare subroutine, may I ask this part of the What is the role of this part? Is it asked to prepare for solving the tridiagonal matrix?
I look forward to your reply, thanks!

[mathrack]

Hello,

When calling the derivative subroutines, one should provide arrays to solve the tri-diagonal linear system. For instance, https://github.com/xcompact3d/Incompact3d/blob/master/src/transeq.f90#L126 :

    call derx (te1,tb1,di1,sx,ffx,fsx,fwx,xsize(1),xsize(2),xsize(3),0,ubcx*ubcy)

The arrays ffx, fsx and fwx are computed at the beginning of the simulation, in schemes.f90. See https://en.wikipedia.org/wiki/Tridiagonal_matrix_algorithm

Cheers,
Mathrack

[yzl429]

Hi,
As I read the paper you gave, it can be understood that the NActuatorlines here are only used when performing verification of wing circulation or dynamic stalls, etc., and if they are not applicable then NActuatorlines=0. Is that the understanding? looking forward to your reply!

[nbeb]

Hi,

Correct, NActuatorlines is by default zero unless a different value is set in the input files.

Best,
Nikos

[yzl429]

Thank you very much.

[yzl429]

Dear xcompact developers,
In the subroutine pre_correc(ux,uy,uz,ep) within navier.f90, when the boundary condition nclx1==2 is met, the pressure gradient dpdyx1(j,k) is used to correct the velocity: uy(1,j,k) = bxy1(j,k) + dpdyx1(j,k). However, in the earlier subroutine gradp(px1, py1, pz1, pp3), when the boundary condition nclx1==2 is met, dpdyx1(j,k) is calculated as py1(1,j,k)/gdt(itr), normalizing the pressure gradient. My question is whether py1(1,j,k) itself already incorporates a time component. Therefore, in uy(1,j,k) = bxyn(j,k) + dpdyxn(j,k), dpdyxn(j,k) appears to be equivalent to py1(1,j,k).

[mathrack]

Hello, this discussion seems to drift. The last update is completely off-topic compared with the initial question. I will lock the present discussion.