Hi everyone,

Now I am running a simulation and facing CFL errors. Although I have read the previous thread, changed namelsit setting and run the simulation again, I still couldn't solve my problem. When I reduced time step, it worked for the first one and half hour and then it stopped with CLF error and segmentation fault. But, As far as I understand, according to manual there are two time steps, RK3 time step and acoustic time step. These time steps are limited according to Courant numbers to avoid CFL error. If i set up according to recommended namelist, the set-up time step is less than maximum time step. But, I am still wondering why there is still CFL error although I set up the model time step which is smaller than maximum time step. I would like to know why there is still error. is there any other points I need to consider for that kind of problem?

When I read previous thread, I found smooth_cg_topo = .true function. Now I am running the simulation with 30m resolution geogrid data. The error is also found in domain 4 where 30m resolution is applied. I would like to know how this function works. How can I find whether the error occurs in the boundary region? I don't understand what smoothing really means. Does it means " this function removes the data of 30 m resolution data in the boundary region"? How does it affect on calculation of wind and other variable?

Any help or comment is appreciated.

Thank you in advance for your time.

Best regard,

Khin

Now I am running a simulation and facing CFL errors. Although I have read the previous thread, changed namelsit setting and run the simulation again, I still couldn't solve my problem. When I reduced time step, it worked for the first one and half hour and then it stopped with CLF error and segmentation fault. But, As far as I understand, according to manual there are two time steps, RK3 time step and acoustic time step. These time steps are limited according to Courant numbers to avoid CFL error. If i set up according to recommended namelist, the set-up time step is less than maximum time step. But, I am still wondering why there is still CFL error although I set up the model time step which is smaller than maximum time step. I would like to know why there is still error. is there any other points I need to consider for that kind of problem?

When I read previous thread, I found smooth_cg_topo = .true function. Now I am running the simulation with 30m resolution geogrid data. The error is also found in domain 4 where 30m resolution is applied. I would like to know how this function works. How can I find whether the error occurs in the boundary region? I don't understand what smoothing really means. Does it means " this function removes the data of 30 m resolution data in the boundary region"? How does it affect on calculation of wind and other variable?

Any help or comment is appreciated.

Thank you in advance for your time.

Best regard,

Khin