|
[Sponsors] |
January 9, 2013, 09:54 |
Water drop falling too slow - Interfoam
|
#1 |
Senior Member
Daniele Vicario
Join Date: Mar 2009
Location: Novara, Italy
Posts: 142
Rep Power: 17 |
I wanted to sim the falling of a drop into water. Nothing complicated (!), I just followed the dam tutorial.
The problem is that the drop is falling too slow (from steady: 50mm in 1.2s) and the velocity is not increasing. Please see enclosed pictures about alpha and U. Here is checkmesh result: Code:
Mesh stats points: 1520469 faces: 4461972 internal faces: 4430208 cells: 1470988 boundary patches: 3 point zones: 0 face zones: 0 cell zones: 0 Overall number of cells of each type: hexahedra: 1448660 prisms: 0 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 0 polyhedra: 22328 Checking topology... Boundary definition OK. ***Total number of faces on empty patches is not divisible by the number of cells in the mesh. Hence this mesh is not 1D or 2D. Cell to face addressing OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces ... Patch Faces Points Surface topology defaultFaces 15876 16169 ok (non-closed singly connected) atmos 0 0 ok (empty) wall 15888 16181 ok (non-closed singly connected) Checking geometry... Overall domain bounding box (0 0 0) (0.2 0.2 0.2) Mesh (non-empty, non-wedge) directions (0 0 0) Mesh (non-empty) directions (0 0 0) All edges aligned with or perpendicular to non-empty directions. Boundary openness (2.34348e-015 2.34348e-015 -2.43385e-014) OK. Max cell openness = 1.71543e-016 OK. Max aspect ratio = 0 OK. Minumum face area = 6.93889e-007. Maximum face area = 1.11156e-005. Face area magnitudes OK. Min volume = 5.7801e-010. Max volume = 3.70593e-008. Total volume = 0.008. Cell volumes OK. Mesh non-orthogonality Max: 25.2571 average: 3.5358 Non-orthogonality check OK. Face pyramids OK. Max skewness = 0.333721 OK. Coupled point location match (average 0) OK. Mesh OK. U Code:
dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { atmos { type pressureInletOutletVelocity; value uniform (0 0 0); } wall { type fixedValue; value uniform (0 0 0); } defaultFaces { type fixedValue; value uniform (0 0 0); } } Code:
dimensions [1 -1 -2 0 0 0 0]; internalField uniform 0; boundaryField { atmos { type totalPressure; p0 uniform 0; U U; phi phi; rho rho; psi none; gamma 1; value uniform 0; } wall { type buoyantPressure; value uniform 0; } defaultFaces { type buoyantPressure; value uniform 0; } } Code:
dimensions [0 0 0 0 0 0 0]; internalField uniform 0; boundaryField { wall { type zeroGradient; } atmos { type inletOutlet; inletValue uniform 0; value uniform 0; } defaultFaces { type empty; } } The water is a sphere with radius=8mm. Flow is laminar. g is defined as: Code:
dimensions [0 1 -2 0 0 0 0]; value ( 0 0 -9.81 ); Code:
phase1 { transportModel Newtonian; nu nu [ 0 2 -1 0 0 0 0 ] 1e-06; rho rho [ 1 -3 0 0 0 0 0 ] 1000; CrossPowerLawCoeffs { nu0 nu0 [ 0 2 -1 0 0 0 0 ] 1e-06; nuInf nuInf [ 0 2 -1 0 0 0 0 ] 1e-06; m m [ 0 0 1 0 0 0 0 ] 1; n n [ 0 0 0 0 0 0 0 ] 0; } BirdCarreauCoeffs { nu0 nu0 [ 0 2 -1 0 0 0 0 ] 0.0142515; nuInf nuInf [ 0 2 -1 0 0 0 0 ] 1e-06; k k [ 0 0 1 0 0 0 0 ] 99.6; n n [ 0 0 0 0 0 0 0 ] 0.1003; } } phase2 { transportModel Newtonian; nu nu [ 0 2 -1 0 0 0 0 ] 1.48e-05; rho rho [ 1 -3 0 0 0 0 0 ] 1; CrossPowerLawCoeffs { nu0 nu0 [ 0 2 -1 0 0 0 0 ] 1e-06; nuInf nuInf [ 0 2 -1 0 0 0 0 ] 1e-06; m m [ 0 0 1 0 0 0 0 ] 1; n n [ 0 0 0 0 0 0 0 ] 0; } BirdCarreauCoeffs { nu0 nu0 [ 0 2 -1 0 0 0 0 ] 0.0142515; nuInf nuInf [ 0 2 -1 0 0 0 0 ] 1e-06; k k [ 0 0 1 0 0 0 0 ] 99.6; n n [ 0 0 0 0 0 0 0 ] 0.1003; } } sigma sigma [ 1 0 -2 0 0 0 0 ] 0.07; The sim is running without any problem. Courant Number is well respected and residuals are ok. It seems phase2 is too viscous... I'm sure it's a silly mistake of mine but where ? Please be kind if you know it Thanks.
__________________
Daniele Vicario blueCFD2.1 - Windows 7 |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Modelling falling solid sphere using interFoam VOF model | eelcovv | OpenFOAM Running, Solving & CFD | 6 | August 7, 2021 21:52 |
interFoam Average velocity of water only! | dsanza | OpenFOAM Post-Processing | 5 | August 3, 2015 12:44 |
question about simulation of falling water film | mengyue1 | FLUENT | 2 | March 30, 2014 10:16 |
Problems with BCs in muliphase flow with water falling from a reservoir | Paul_l | FLUENT | 2 | March 11, 2011 04:59 |
uptodate water distribution network | fredius,magige,tanzanian,(e.a) | Main CFD Forum | 0 | January 27, 2002 07:10 |