Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

Time step size estimate

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.

X

xtian15

Member
Hi,
My question is about the time step size when running MPAS with full physics. I am aware that the time step sizes are often given the value of 6x of grid spacing in km. Under the "6x" scenarios, what should the value of "config_dynamics_split_steps" be? I am asking because when I tried to run a 3-60 variable resolution mesh, simulations with step sizes greater than 10s tend to explode, in which the "config_dynamics_split_steps=1". Thanks in advance for your help!
 
The default value for "config_dynamics_split_steps" is 3; did you have a specific reason for changing this parameter? It's probably worth trying a test run with the following parameters set to their default values:
Code: 
    config_time_integration_order = 2
    config_split_dynamics_transport = true
    config_number_of_sub_steps = 2
    config_dynamics_split_steps = 3
 
Thanks Michael!
I wanted to change the config_dynamics_split_steps into 1 hoping to save a bit of running time, as 3 is to integrate the dynamics 3 times. But config_dynamics_split_steps=1 makes the system quite unstable so I'll just change it back to the default 3. Thanks again for confirming!
 
You must log in or register to reply here.
Top