Learning Forum

[Simão Martins]

I have a big model where I'm solving a reacting flow using the CESE solver with Chemistry. I need to output the pressure and temperature values at certain elements only and with small timesteps. The problem is that the D3PLOT becomes too big if I choose a small timestep because all data is being saved for all elements. I tried to use the  *CESE_DATABASE_ELOUT card but it doesn't give the correct output for chemically reacting flows (see the figure below). The other options for binary and ASCII output also don't seem to work with the CESE solver (*DATABASE_BINARY_D3PART, * DATABASE_ASCII, etc).

Is there any other way to reduce the d3plot's without increasing the timestep or to output the CESE results for certain elements only?

[Reno Genest]

Hello Simao,

The *CESE_DATABASE_ELOUT keyword does not work with chemically reacting flows. Here is more information from the LS-DYNA User Manual Vol III:

"*CESE *CESE_DATABASE_ELOUT
3-56 (CESE) master@a5e83d6b2 (11/08/23)
2. Restrictions. The *CESE_DATABASE… cards (pointout/elout) are restricted to
CFD-only problems. They do not give correct results for chemically reacting
flow where *CESE couples with *CHEMISTRY."

You can control results that get stored in the d3plot using *DATABASE_EXTENT_BINARY.

Also, you can change the output frequency of the d3plot using a load curve (*DEFINE_CURVE) to have an output frequency vs time. This way, you could have a low frequency of output at times when output is not needed or not important and a high output frequency when it matters. See the LCDT parameter of *DATABASE_BINARY_D3PLOT.

Also, have a look at *CONTROL_OUTPUT as there might be quantities that you can omit from the d3plot.

 

Reno.