[gmx-users] water flow

Alex nedomacho at gmail.com
Tue Jun 12 19:37:05 CEST 2018

Hi Justin,

Looking at acc-grps text in the manual, it's a bit unclear how a 
constant flow rate would be achieved in this case. Is a constant force 
in the amount of molecule mass, times the acceleration vector applied to 
each molecule in the group, or is there actual acceleration magically 



On 6/12/2018 8:24 AM, Justin Lemkul wrote:
> On 6/11/18 7:38 PM, Alex wrote:
>> Hi all,
>> I'm trying to explore pressure-induced processes, i.e. externally 
>> induced
>> water flow across a porous membrane that spans the entire box in XY. 
>> There
>> are obvious choices:
>> 1. Introduce the same type of a membrane without pores and make it a 
>> piston
>> with pull code, e.g. constant force or tiny constant velocity along Z.
>> 2. Apply constant force pull directly to the entire solvent group.
>> Any other ideas on osmosis-like processes? Has anyone tried any of the
>> options above?
> I would think the pull code would be more headache than it's worth in 
> this case. I'd simply try inducing the flow with acc-grps.
> -Justin

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