|
[Sponsors] |
DeltaT keeps decreasing after droplet impact on the surface. |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
April 12, 2021, 11:28 |
DeltaT keeps decreasing after droplet impact on the surface.
|
#1 |
New Member
SONG
Join Date: Apr 2021
Posts: 7
Rep Power: 5 |
Hello,
I am a freshman on the simulation of droplet impact and I have a question on the set of wall's dynamic contact angle. I set the dynamic contact angle in fold 0/alpha.water, before the droplet impact on the wall, the case runs well and deltaT is about 1e-7. However, after the droplet impact on the wall, the time step keeps decreasing. Does anyone have some suggestions to solve the problem? Here is the alpha.water file \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; object alpha.water; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 0 0 0 0 0 0]; internalField uniform 0; boundaryField { inlet { type fixedValue; value $internalField; } outlet { type inletOutlet; value $internalField; inletValue $internalField; } walls { type dynamicAlphaContactAngle; theta0 70; thetaA 90; thetaR 40; uTheta 0.01; limit gradient; value $internalField; } } // ************************************************** *********************** // |
|
April 12, 2021, 16:42 |
|
#2 |
Senior Member
krishna kant
Join Date: Feb 2016
Location: Hyderabad, India
Posts: 133
Rep Power: 10 |
Hi SONG,
As per my experience this happens when the fragmentation of the liquid blob is very high for your given parameters and grid being very fine. One option is you can make the time step fixed. It will cause some loss of mass but make sure your fixed value is sufficiently small so the losses are not significant. |
|
April 14, 2021, 05:07 |
|
#3 | |
New Member
SONG
Join Date: Apr 2021
Posts: 7
Rep Power: 5 |
Hi,krishna.
Initial droplet velocity is only 1m/s and the droplet free falling with gravity from 4mm above the wall. Based on experiments resutls, no droplet splash (fragmentation)occourss under this condition. The initial mesh is 8 on per droplet diamenter, refine level is 4, and the minimum mesh is 0.015625mm. In additon, if the contact angle is set as constant contact angle instead of dynamic contact angle, the droplet can deposit on the wall with deltaT around 1e-7. I will try the fixed time step and to check is the case can run successfually. Quote:
|
||
Tags |
deltat, droplet impact, dynamic contact angle |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
SU2 7.0.7 Built on CentOS 7, parallel computation pyscript mpi exit error? | EternalSeekerX | SU2 | 3 | October 9, 2020 19:28 |
water impact surface under electrical field | XinXin | OpenFOAM Programming & Development | 1 | July 26, 2020 22:58 |
How to patch a water droplet with smooth surface? | Hossein1 | FLUENT | 0 | January 13, 2017 10:25 |
Simulation of charge redistribution of a droplet due to impact on solid | multiphaser | Main CFD Forum | 0 | October 5, 2016 05:04 |
Droplet impact on a solid surface | mwithoutm1901 | Main CFD Forum | 2 | June 25, 2016 23:17 |