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Advection-Diffusion with source term

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  • #4168
    mithdradates
    Participant

    Hello, I’m relatively new to the LB methods (and especially to OpenLB), so sorry if some of my questions sound stupid.

    So, I’m trying to model evaporation of a droplet following the work of C. Zhang, P. Cheng, W.J. Minkowycz “Lattice Boltzmann simulation of forced condensation flow on a horizontal cold surface in the presence of non-condensable gas”. They use source term for their temperature distribution LB equation, so I was wondering if there is an advection-diffusion model with a source term in OpenLB ? If not, is there any way to implement it (a short guide would be very appreciated) ?

    EDIT: I also have a second question – considering that I’m using Peng-Robinson EOS for the interparticle potential and this EOS contains temperature explicitly, can I couple NSLattice and ADLattice by simply utilizing the temperature from ADLattice ?

    Thank you.

    • This topic was modified 3 years, 5 months ago by mithdradates.
    #4171
    mgaedtke
    Keymaster

    Hi mithdradates,

    to 1: I implemented the sourced advection diffusion model by Seta (https://journals.aps.org/pre/abstract/10.1103/PhysRevE.87.063304) a few month ago and it will be included in the next release, which will become available soon.

    to 2: Yes, using the temperature from the ADlattice for this purpose should be the way to go. To get an idea how to achieve this in OpenLB you can have a look at the boussinesq coupling in src/dynamics/navierStokesAdvectionDiffusionCouplingPostProcessor2D . h and .hh

    Best, Max

    #4172
    mithdradates
    Participant

    Hello Max,

    1: That sounds great, thank you for your work! Do you have any information on the date of the next release (somewhere in April or sooner \ later)?

    2: So I don’t actually need coupling through boussinesq force term if I have a temperature already in my EOS, is that correct? I mean can I simply reimplement coupling by using PengRobinson pontetial’s overloaded () operator to include temperature from the ADLattice? Just want to make sure I understood you correctly.

    I also have some additional questions (as you seem to be very knowledgeable on the subject), if you don’t mind.

    3: Are there any in-built functions to calculate derivatives or divergence in OpenLB? I found AnalyticalDiffFD1D functor (from the description: “Derivative of a given 1D functor computed with a finite difference”), but as far as I understand it is suited to compute derivatives of functions (via (f(x + eps) – f(x)) / eps), not physical values like velocity or density.

    4: Is there a zero-gradient (neumann) boundary for pressure in OpenLB?

    Hope I didn’t take too much of your time. Thank you!

    • This reply was modified 3 years, 5 months ago by mithdradates.
    #4174
    mgaedtke
    Keymaster

    Hi mithdradates,

    to 1: we are currently preparing the release. we’re about to finalize it in the next few months.

    to 2: As far as I understand your plan, yes you can it like described.

    to 3: Yes, there are: for example have a look at SuperLatticePhysStrainRateFD3D

    to 4: OpenLB has several convection boundaries implemented, if that is what you are looking for. To get an idea, see https://doi.org/10.4208/cicp.091009.290910s

    #4175
    mithdradates
    Participant

    Hello Max,

    to 1 & 2: Okay, thank you!

    to 3: As far as I understand, I can use SuperFiniteDifference3D to calculate derivatives. Correct?

    to 4: I was looking for Neumann outflow condition (dP/dn = 0 – zero gradient) for pressure.

    Thanks again!

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