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# Lattice Boltzmann method

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1.

Looks interesting, is this also used for weather/climate models?

Comment Source:Looks interesting, is this also used for weather/climate models?
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2.

this is what i am trying to find out :-) but at least it works good for water up to a fairly high reynolds number and some have added turbulence support. Ill add more on this later. My intention was to see if and where it can be used in complement to the FE modeling used. But we have a bunch of math and climate researchers here so they might tell us. For modeling hydrodynamics you have

• FEM extended simplified with Galerkin or Ritz variational method

• Particle in cell method

• Lattice Boltzmann - which seems to have most momentum right now, compared to "particle in cell".

Check these movies out on youtube some in the middle shows higher reynold flows

Comment Source:this is what i am trying to find out :-) but at least it works good for water up to a fairly high reynolds number and some have added turbulence support. Ill add more on this later. My intention was to see if and where it can be used in complement to the FE modeling used. But we have a bunch of math and climate researchers here so they might tell us. For modeling hydrodynamics you have * FEM extended simplified with Galerkin or Ritz variational method * Particle in cell method * Lattice Boltzmann - which seems to have most momentum right now, compared to "particle in cell". Check these [movies out on youtube](http://www.youtube.com/results?search_query=lattice+boltzmann+method&aq=1) some in the middle shows higher reynold flows
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3.

just found some papers that indicate LBM are easy and accurate for flows in porous matters. I ll add that. Also my short term goal is to see if it can or has been used to model the notoriously difficult aerosol-cloud interaction, like sulfur compounds.

Comment Source:just found some papers that indicate LBM are easy and accurate for flows in porous matters. I ll add that. Also my short term goal is to see if it can or has been used to model the notoriously difficult aerosol-cloud interaction, like sulfur compounds.
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4.

I added some more references to the page and I have a bunch of others that I will start adding.

Comment Source:I added some more references to the page and I have a bunch of others that I will start adding.
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5.

Staffan, thanks for editing about the lattice boltzmann. it would eventually be good to say a bit more about the equations in the Wiki entry:

Collision step: f i t(x⇀,t+δ t)=f i t(x⇀,t)+1Τ f(f i eq−f i))

Streaming step: f i(x⇀+δ⇀ t,t+δ t)=f i t(x⇀,t+δ t)

For example, what is meant by $f^{eq}$? In this link http://www.science.uva.nl/research/scs/projects/lbm_web/lbm.html which was listed on the wikipedia site there are more explanations, here $f^{eq}$ is some equilibrium distribution, however their lattice Boltzmann version has e.g. different signs (different relaxation?) as in the Wikipedia version and it is not clear to me wether their $c_i$ is supposed to be the same as the $e_i$ in the Wikipedia version. In short: I don't know wether the Wikipedia entry is so useful, this netherland site looks a bit better, but I dont know either wether its a good starting point.

Comment Source:Staffan, thanks for editing about the lattice boltzmann. it would eventually be good to say a bit more about the equations in the Wiki entry: Collision step: f i t(x⇀,t+δ t)=f i t(x⇀,t)+1Τ f(f i eq−f i)) Streaming step: f i(x⇀+δ⇀ t,t+δ t)=f i t(x⇀,t+δ t) For example, what is meant by $f^{eq}$? In this link <a href="http://www.science.uva.nl/research/scs/projects/lbm_web/lbm.html">http://www.science.uva.nl/research/scs/projects/lbm_web/lbm.html</a> which was listed on the wikipedia site there are more explanations, here $f^{eq}$ is some equilibrium distribution, however their lattice Boltzmann version has e.g. different signs (different relaxation?) as in the Wikipedia version and it is not clear to me wether their $c_i$ is supposed to be the same as the $e_i$ in the Wikipedia version. In short: I don't know wether the Wikipedia entry is so useful, this netherland site looks a bit better, but I dont know either wether its a good starting point.
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6.

I will add some more info and i also want to add an animation from an open source impl in the reference section, but in essence you are right its different relaxations. Ill try to answer by adding to the page.

Comment Source:I will add some more info and i also want to add an animation from an open source impl in the reference section, but in essence you are right its different relaxations. Ill try to answer by adding to the page.