Learning Forum

[Saeed]

Hello,

I did a SPH simulation and I faced an issue, all the sph settings are default I just changed the element size to 0.005 m since my particle size is 0.02m. the problem is after the particles are added , they do not change their position anymore and do not move. it seems like they are fixed and just vibrate in their place. in the attached figure all the particles have not moved in the past 3s of the simulation. 

Can you please help me with that ?

Thanks

[Lucas Bertollo Baggio]

Helo Saeed,

Where are the SPH Elements? How are you injecting those particles (and fluid)? Is gravity correctly set?

 

regards, Lucas

[Saeed]

Dear Lucas,

I just made sph invisible to look at particles. And yes the gravity is enabled correctly in z axis. both sph and particles are added through a circular surface from the top of the tank. sph is added from 0 to 1 s and then particles are added from 1 to 2s of the simulation time.

Thanks

[Lucas Bertollo Baggio]

And when to the particles stop moving?!

 

[Saeed]

after all particles are added to the system

[Lucas Bertollo Baggio]

And the SPH countinues falling?

[Saeed]

all the sph are added between 0-1s of simultation and after that the particles will be added from 1to 2s and then no particles or sph elements will be added 

[Lucas Bertollo Baggio]

but do they still move? (the sph elements)

[Saeed]

yes the SPH elemetns move

[Lucas Bertollo Baggio]

Could you give more setup details so I might help you? 

Do you have any active motion frame? CFD Coupling?

[Saeed]

I have included my Rocky simulation in the attached google drive.

https://drive.google.com/drive/folders/1RfPtwrB7W0v3KMfgOStaOg7CG5iZb5Gj?usp=drive_link

Thanks 

[Lucas Bertollo Baggio]

I can't access your simulation from this forum. I'd suggest you to open a ticket for the support team if we can't go further on this chat. 

[Saeed]

I have a student account so I can not do that.

I am simulating a mixing tank , i have a motion frame which I defined and added to the impeller of tank , I do not have cfd coupling and it is just sph since i have very large particles. 

[Lucas Bertollo Baggio]

And which modules did you enable? 

[Saeed]

sph density monitor and contact overlap monitor 

[Lucas Bertollo Baggio]

Have you created any particles time selection user process? are the Particles main entity visible in the 3D View?

[Saeed]

I do not know how to creat particle time selecetion can you please help me with that ?

and yes the particles are visible , i have attached an image in my first message 

[Lucas Bertollo Baggio]

You can search in the user manual or check the Tutorial 8 to learn more about particles time selection (it is a user process for postprocessing).

 

If your simulation is just an inlet that injects sph and particles with an impeller that rotates inside the tank, I can't see why this is happening. 

Unfortunately, I can't access your simulation file, but I would suggest you to setup it all again, and maybe fill the tank with two separate inlets (one for SPH and one for Particles) or with a volumetric inlet.

 

best regards,

Lucas 

 

 

[Saeed]

Hi,

I ran the simmulation again and same issue came up. I first added the particles with volumetric method then I added the SPH ellements, as you can see in two different time steps the particles does not move. my particles have smaller density than sph but still they do not move towards the surface.