Search found 9 matches

by yj7054
Thu Dec 20, 2018 4:36 am
Forum: ROMS Problems
Topic: Keep net volume as a constant without Volcons
Replies: 0
Views: 530

Keep net volume as a constant without Volcons

Dear All, My purpose: Keep the net volume as a constant without turning on the VolCons My design: LBC(isFsur) == Clo Cha Cha Cha ! free-surface LBC(isUbar) == Clo Cla Cla Cla ! 2D U-momentum LBC(isVbar) == Clo Cla Cla Cla ! 2D V-momentum LBC(isUvel) == Clo Rad Rad Rad ! 3D U-momentum LBC(isVvel) == ...
by yj7054
Sun Dec 02, 2018 10:26 pm
Forum: ROMS Problems
Topic: 'nfast' and 'ndtfast' on Barotropic time step
Replies: 5
Views: 941

Re: 'nfast' and 'ndtfast' on Barotropic time step

Nope , there are actually M* barotropic timesteps :!: The reason for it is that the cosine-square shape filter needs to provide time-averaged values of ubar , vbar , and zeta centered at the n+1 baroclinic timestep, which gives us second-order temporal accuracy for time-averaged barotropic motions....
by yj7054
Sun Dec 02, 2018 5:46 am
Forum: ROMS Problems
Topic: 'nfast' and 'ndtfast' on Barotropic time step
Replies: 5
Views: 941

Re: 'nfast' and 'ndtfast' on Barotropic time step

Read this explanation on WikiROMS: https://www.myroms.org/wiki/Numerical_Solution_Technique#Time-Stepping_Overview and the Shchepetkin papers. Hi John, Thank you for your reply. I read the explanation before but it was complex for me. Now I think I got the main idea roughly: There are M* barotropic...
by yj7054
Fri Nov 30, 2018 2:53 am
Forum: ROMS Problems
Topic: 'nfast' and 'ndtfast' on Barotropic time step
Replies: 5
Views: 941

'nfast' and 'ndtfast' on Barotropic time step

Dear all, nfast : Number of barotropic timesteps needed to compute time-averaged barotropic variables centered at time level n+1 ndtfast : Number of barotropic timesteps between each baroclinic timestep. I am confused with the time-stepping in ROMS. For example, I set dt = 150s, ndtfast = 30 in ocea...
by yj7054
Thu Nov 15, 2018 4:54 am
Forum: ROMS Problems
Topic: Transport adjustment on the boundary
Replies: 6
Views: 976

Re: Transport adjustment on the boundary

You had a post earlier about using Huon etc to compute transport, and you said you vertically integrated these. But really it's a vertical sum because the layer thickness is already in there. I hope you didn't put in an extra delta-z (Hz). Really thanks for your reply. I did not put in an extra del...
by yj7054
Tue Nov 06, 2018 10:37 pm
Forum: ROMS Problems
Topic: Transport adjustment on the boundary
Replies: 6
Views: 976

Re: Transport adjustment on the boundary

if you use flather boundary conditions (Fla), it does not guarantee that the mass flux imposed by the ubar on the boundary will be imposed at the boundary. -j Hi John, Thank you very much! Excatlly, the ubar model calculated is usually different from what the OBCs provide in the boundary files. In ...
by yj7054
Tue Nov 06, 2018 3:43 am
Forum: ROMS Problems
Topic: Transport adjustment on the boundary
Replies: 6
Views: 976

Re: Transport adjustment on the boundary

other than that, there is no guarantee that the volume flux across all open boundaries will balance. For example, if you had an estuary with only one open boundary then the flux will not balance. The fluxes across each open boundary are independent from other open boundaries (unless you activate vo...
by yj7054
Tue Nov 06, 2018 1:10 am
Forum: ROMS Problems
Topic: Transport adjustment on the boundary
Replies: 6
Views: 976

Transport adjustment on the boundary

Hi All, I realized that the volume transport the model got was different from the volume tranpsort which the boundary files provied . It seems that the model did some adjustment to keep the net volume balance in the domain regardless of the boundary files. I did not turn on the VolCons to keep volum...
by yj7054
Mon Nov 05, 2018 9:33 am
Forum: ROMS Problems
Topic: Volume not conserved.
Replies: 3
Views: 1720

Re: Volume not conserved.

Hi, I also hold the same confusion with you, so did you figure out your problem?
How to check the volume conservation?