About dpd thermostat

Dear lammps,

I ran the couette flow with the dpd thermostat working.
It was confirmed through the log file that the temperature converged to 0.7 even though the temperature was set to 1.0.
I want to set the temperature to 1.0, but is there any way?

Or is it difficult to keep the temperature consistent because the couette flow is speeding up the wall? I would be grateful if you could tell me the reason.

This is my input file and log file.

input_couette flow3_3d_dpd.txt (1.9 KB)
log.lammps (61.1 KB)

Hi @please,

There is a large literature on the computation and control of temperature in flowing atomic and molecular systems which can be a tricky topic to get into in the first place. A starting point could be the careful reading of the How-to pages of the LAMMPS manual concerned with Thermostats and NEMD. The work (both books and papers) of Todd and Daivis is also very informative on these topics. Please also have a look at the temp/profile command which is more suited for velocity biases computation during fluid shearing along a given axis. With this quite high quantity of informations to consider, I suggest you ask any advisor or colleague about these stuff which are both fundamental and quite technical. This is the best way to process them in a meaningful way.

Finally, concerning your convergence issue, I suggest you take a careful reading on how the DPD pair_style works because you are basically thermostating you sheared fluid twice using both the pair_style and the fix temp/rescale which is definitely not a good thing to do.