# Need Confirmation - Eulerian solver for tiny particules

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 August 29, 2012, 11:26 Need Confirmation - Eulerian solver for tiny particules #1 Senior Member   HECKMANN Frédéric Join Date: Jul 2010 Posts: 249 Rep Power: 15 Hi everyone, it would be nice if somebody can give me some confirmations on the general aspect of my algorithm and the "code" that follows (especially the translation of the equations). I want to setup an unsteady Eulerian solver to compute the behavior of tiny particles in a fluid (only the fluid impact the particules motion through the drag). Nomenclature : - volume fraction of the particles - velocity of the particles - function of the relative Reynolds number - time respond of the particle - velocity of the fluid Continuity equation : Momentum equation The algorithm I have in mind : 1) setup a "phi_alpha" flux equal to 2) initialize this flux in the createfield with: Code: "linearInterpolate(alpha)*linearInterpolate(u) & mesh.Sf()" 3) solve the continuity equation using the following code: Code: fvScalarMatrix cEqn ( fvm::ddt(alpha) + fvc::div(alpha_phi) ); cEqn.solve() 4) update the flux phi_alpha with: Code: alpha_phi -= cEqn.flux(); 5) compute the relative Reynolds number, the function and 6) solve the momentum equation using: Code: fvVectorMatrix uEqn ( fvm::ddt(alpha, u) + fvm::div(alpha_phi, u) == fRe / Tau * alpa * (V – u) ); uEqn.solve() My questions are: i) I'm not sure of the step 4... I kind of reproduce the simpleFoam code. Is there any documentation somewhere about the command ".flux" ? ii) I'm not sure of the translation of the momentum equation step 6. Do I need to use a specific formulation for the source term ? Does the solver identify the last "u" by itself ? Thank you in advance for reading this. Last edited by fredo490; August 29, 2012 at 11:28. Reason: Tiny corrections

 September 13, 2012, 03:24 #2 Senior Member   Gerhard Holzinger Join Date: Feb 2012 Location: Austria Posts: 317 Rep Power: 26 have a look into twoPhaseEulerFoam or bubbleFoam and the thesis of H. Rusche. They all deal with a Eulerian formulation of two-phase fluid flows. I would recommend to get into bubbleFoam or twoPhaseEulerFoam and remove everything you don't need. Particles with constant diameter and only drag as momentum exchange should not be a big problem. Last edited by GerhardHolzinger; September 13, 2012 at 03:27. Reason: added clarifiaction

 Tags equations, euler, particles