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Malcolm Zaloon

flow variation

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Hello guys.


I have a cylinder, where a sphere of honey in perfect center alignment, and a viscous fluid fall in top of cylinder... 




what happens? the flow in laterals of cylinders are almost perfect with no variation...(yeah, this is expected) ;)

but, i thinking how can i "inject" some variation without change alignment or shape of emmiter (need be a perfect sphere falling).




i´m trying to achieve this effect on sides of cylinder:



I really want a control of flow on laterals, to do some nice fillets/filaments.


what i try:


1.variable viscosity, but looks ugly, honey appear tickness variation on top because various viscosities.

2.variable density... simple do not look nice.

3.painted some friction on sides of cylinder... but again simple do not look nice or good variation as in shutterstock picture,



Any ideias, examples?

Edited by Malcolm Zaloon

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decrease viscosity and add surface tension.
BUT. result will be quite symmetrical cause all these irregularities due to some variations in material of honey and deflectors, so add some variable friction etc..


Edited by bloomendale

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oh... surface tension? where?


anyway, i think this will not make a really expressive drips like on image.. (its very long ones...)


hmmm... still trying...

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gas surface tension microsolver.. or make similair via vex(vops) - this way you'll have more control by masking areas of vel field where you want surface tension to act.

btw, attached pic (just surface tension.. no friction maps etc)

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Wow! i havent see screenshot before...


it´s perfect!


can you share scene file to i learn from?


i don´t know how to use masks in a proper way yet. i tried without success. (i´m new on houdini)


thanks in advance man.

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If you need to choreograph it with more control, you could use a radial pump volume on top of the cylinder, to nudge the fluid at the right places.

Here I used a radial noise, but for exact control you could build the velocity volume from geometry.



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my evolution:



In your first screenshot, you achieve exactly look i wish to achieve, can you explain your parameters or share scene? You used the trick of 
radial pump on first one? Constant of variable viscosity?
I play with some settings and add surface tension, its look nice, but i have not so long beautiful drips, i make them using noise on density.
in this stage, i´m avoiding to use variation on viscosity, so, it´s constant.
What a scale of your first scene? When i try to make scene on real scale, my collisions not work as expected...so my scene is bigger, and i 
try compensate settings... 
there is a way to fix collision on tiny scale simulation? (ex. a 8cm height irregular cylinder)
the current scene(screenshot) the cylinder have 80cm!! :(
note: on source volume activation i have a expression "$SF == 1" (i have no 100% sure, but i believe this is correct emission method)
Thanks Eetu!

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