I wanna change harmonic to biharmonic

[kobl1201]

Hello

I have some questions.

Until now, i have run the ROMS model using the harmonic mixing coefficients, which are 1 m2/s for tracer and momentum.

But i wanna change biharmonic mixing coefficient.

Therefore, i just change the cpp opotion.

EX) UV_VIS2 -> UV_VIS4
TS_DIF2 -> TS_DIF4

Can i change only two things or need to change more option at cpp option ???

And i set the coefficient, 1m^2/s for harmonic method. When i change the bi-harmonic method, can i set the same value, 1m^4/s for bi-harmonic??

Thank you~

[kate]

I think that's all you need to do. In this business, we encourage you to try something first, then ask if it doesn't work out.

[kobl1201]

Hi Kate

I change from UV_VIS2, TS_DIF2 to UV_VIS4, TS_DIF4 at the cpp option, respectively, and the value was changed from the VISC2=1m^2/s to VISC4=1m^4/s.

The model finished and then i could get the results.

But i wonder that the VISC2=1m^2/s corresponds to VISC4=1m^4/s or can i need to calculated other method for the biharmonic coefficient.

For example, my model resolution is about 1km, and i set the value of harmonic, VISC2=1m^2/s.

If i change the method of bi-harmonic corresponed to harmonic coefficient, can i change the value of bi-harmonic such as VISC4 = (dx)^2*VIS2, or i just can change the value, VISC4=1m^4/s ???

[kate]

The ROMS manual gives advice about checking damping timescales for various spatial scales with lateral viscosity. You want to keep the damping timescale for 2dx noise about the same, but the two will give different timescales on the 10dx features.