Correspondance param(85) in latest version

[Alexandre Tlili]

Dear Nek community,

I would like to restart a simulation with varied parameters. I was advised to restart it with a small initial timestep, and to gradually increase it over time, until it reaches the CFL-based value. 

Apparently, it used to be possible to set this feature in previous versions using the .rea file (p84=1e-08 and p85=1.2 for instance, with initialDT of 1e-08, increasing geometrically with rate 1.2), but the p85 parameter does not seem to be accessible in the .par file.

Do you know how to reproduce this feature in the latest versions? I am currently using version 20.0-dev.

Thank you for your help.

Best regards

Alexandre Tlili

[YuHsiang Lan]

Hi Alexandre,

The param(85) is still used in setdt (subs1.f). Currently, there is no par-key to set it from par file.

However, you can always set "param(85)=1.2" manually in places like usrdat.

      else IF (PARAM(84).NE.0.0) THEN
         if (dtold.eq.0.0) then
            dt   =param(84)
            dtold=param(84)
            dtopf=param(84)
            return
         else
            dtold=dt
            dtopf=dt
            dt=dtopf*param(85)
            dt=min(dt,param(12))
         endif
      endif

Hope this helps,

Yu-Hsiang

--