Greetings, How does one implement on imposed shear force in MD simulations in general and Molly in particular? For context, see e.g. https://github.com/ziolai/finite_element_electrical_engineering/tree/main/project-based-assignment/making_mayonnaise
Could you point to a particular interaction equation you want to implement?
Molly only works with particle simulations, so finite element or fluid dynamics methods may not be applicable.
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Dear Joe,
We want to implement two interactions.
The first interaction is the random motion of oil droplets in water. This interaction can be modeled be the minimization of the entropic free energy. This term dominates in case of low volume fraction of oil droplets in water.
The second interaction in the deformation of the interface between the oil droplets and water. This interaction can be modeled by the minimization of the interfacial energy. This term dominates in case of high volume fraction of oil droplets in water.
Both interaction depend on the magnitude of external force (dilation or shear) applied to the sample. The entropic interaction depends on the amount of external force via the partition function. The interfacial interaction depends on the amount of external force via the amount of deviation from perfect spheres.
Both interactions have closed-form expressions for the free energy as a function of the volume fraction in case of mono-disperse oil droplets (all oil droplets having the same diameter). We are happy to start MD assuming mono-disperse simulations.
Does Molly allow to derive interaction potentials from free energy potential expressed in terms of the volume fraction of the droplets?
Thank you. Domenico.
I don’t have much experience of what this would look like. If the potential can be calculated as a function of the droplet positions and properties then yes, you should be able to implement it in Molly.
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Thanks!
Are there examples of Molly.jl simulations with post-processing for local values of the mixture fraction of particles or the partition function?
Not that I know of, sorry.
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Many thanks! Good to know that my queries are not naive.
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Not at all, and if you do find something useful then consider contributing it as an example to the documentation.