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Gas advention-diffusion problem

OpenLB – Open Source Lattice Boltzmann Code Forums on OpenLB General Topics Gas advention-diffusion problem

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  • #8548

    Dear Community,

    Resently, I desire to simulate a gas leakage to the air process. In the mannual, I found the particle flows as advection-diffusion problem method, and the advection-diffusion model fort thermal problem.

    I want to ask that can I use the thermal model to solve the concentration forced problem, because the concentration diffusion is similar to thermal diffusion problem?

    Whether it is appropriate to use the particle method to solve gas diffusion problem? Additionally, in the particle diffusion case, is the force which applied to NS lattice constant? How can i modify the force type and the compute mode?



    Yes, you can use ADE to model particle / gas densities transported by a fluid (“NSE lattice”). You can check out the particles/bifurcation3d/eulerEuler case as an example for this.

    You can modify the external force locally, the forcing schemes implemented in OpenLB commonly read it from the descriptors::FORCE field.


    Dear Adrian,

    Thanks for your reply!

    I try to modify bifurcation3d case.

    I query the source code, replace the dragforce class with class BuoyancyForce class and change the partrho parameter to the methane density which is close to the real density in the converter.

    At the same time, I also used a cube as a simulation domain to simulate the phenomenon of gas diffusion. But the program was running with warnings like undefined data, no data present, and the density heat map of the ad lattice was blank.

    I’ve tried several simulations and the dragforce in the example seems to be 1-2 orders of magnitude larger than the BuoyancyForce.

    Is this the main reason for the errors in the program? And how can I define my own force in the coupling process?

    Please help me solve this problem, thank you!


    If you base your case on the Euler-Euler model, the drag force is necessary. The buoyancy force can be added through the descriptors::EXTERNAL_FORCE field so that you have both forces active.


    Dear TimBingert,

    Thank for your reply!

    Could you give me an example, I don’t know where should I use the descriptors::EXTERNAL_FORCE to add buoyancy force, the D3Q19<force>?

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