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SPH-INOUT Condition

Altair Forum User

Hi there,

I am trying SPH INOUT Collector for simulating water flow at a certain speed in a tank and a pole at middle of the tank.

My aim is to capture the vortex formation around the pole.

But first of all I'am unable to define properly the INOUT condition (SPH is moving away from the inlet boundary). A set of SHP Particles moving and collides with other (as shown below)

At outlet I defined atm. pressure function.

I am attaching the deck with the simulation HV video to represent my problem.

Kindly request to consider my problem and suggest some solution for it. SPH.gif.72a5dc9d612c55e09a56cb3a5759f647.gif

Thanking You.

rgrds,

Pritam

Inout_0000.rad

Inout_0001.rad

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Altair Forum User

Hi Pritam,

This vortex formation in RADIOSS is not a viable case.

You can simulate the same in our CFD solver, Acusolve. Please go through a case study on the same at http://www.altairhyperworks.com/html/en-us/rl/ACUSIM/papers/ASME_FEDSM2003_45514.pdf

Altair Forum User

Dear George,

Thank you for your suggestion.

But I want to resolve the problem with INOUT condition. As you have seen in my attachments it is not properly working. The SPH particles are not continues from the inlet boundary (the boundary particles are just moving forward, rather than a continuous flow)

I am attaching a video. I want a similar condition with or without waves.

Kindly request you,please help me out with my problem.

Thanking You.

(credit: Femto Engineering)

Altair Forum User

Hi Pritam,

We don't have a direct load or BCs through which you can create a wave. We have the generic loads like concentrated load, gravity,initial velocity, imposed velocity, imposed displacement..etc

Altair Forum User

Dear George,

My main concern is IN_OUT Collector with a continuous flow with inlet and outlet, which I am not able to get.

That wave video I just share for representation purpose for the continuous flow process (wave is not of concern).

Please help with my concern.

Thanks.

Altair Forum User

Hi Pritam,

We will check to this and will update you very soon.

Altair Forum User

Thank You very much.

Eagerly waiting for your reply.

Altair Forum User

Hi Pritam,

Apologies for a delayed reply and please find the attached sample model on /SPH/INOUT.

For /SPH/INOUT condition create a seperate component collector for the particles to be created assigned with material and property (SPH) and recall the same in part_id of /SPH/INOUT collector. For the inlet surface created make sure that the element normals are towards the flow direction.

model_0000.zip

Altair Forum User

Dear George,

Thanks for your support.

The model is running properly.

1) But as I can see the 'water' component is empty, without any sph particles. A bit confusion with this.

2) As you said earlier for creating waves with generic loads like imposed velocity, imposed disp. etc., which nodes or elements to assign loads as there is no sph particles before.

3) And what will happen if sph is already present in the tank, shall I have to make different component for this and assign contact between this two sph components?

4) For my query consider a case like, an object (say a ball or boat) is floating on the continuously flowing water.

Can you please model a small case for these condition as I share a video earlier with floating boats on waves.

Regarding this attaching a file(please refer pages 25-28).

Thanking you.

Ship_Dambreak_SPH.pdf

Altair Forum User

Hi Pritam,

As mentioned in the last reply the water component is a kind of dummy collector created for the SPH particles those are created by /SPH/INOUT method.

I have created a pole and has defined the interface between the SPH and pole.

Similarly, please try with existing SPH particles.

model_0000.rad

Altair Forum User

Thank you very much George,

I cleared most of my doubts, but one thing left.

Which nodes to assign generic loads (imp vel, imp disp. etc.) for generation of waves. Unable to create on the sph particles coming from inlet surface.

Please suggest on this query.

Thanking You.

Altair Forum User

Hi Pritam,

As a workaround you can create some SPH particles (don't go for very low pitch, that is not much finer particles) initially in the tank and generate SPH using /SPH/INOUT method. This may create a similar effect.

Altair Forum User

Thank you very much for your suggestion.

I will try this approach and come out with the observation.

thanks.

Altair Forum User

Hi,

What type of contact to be provide between two sph components.

sph-sph contact.

Thanking You.

Altair Forum User

Hi Pritam,

You can try with Type 7 between them.

Meanwhile as another workaround, you can also add the dummy SPH collector and existing SPH collector together as master components and slave nodes as tank or pole...etc.

Altair Forum User

Hi George,

That's absolutely fine, but i think there should be a contact between the dummy sph and the existing sph for the effect. If i am applying type 7 between two sph components, than there will be absence of master surface, which collector will act like master surface.

Thanks.

Altair Forum User

Hi Pritam,

Please check the model which I have sent you earlier. Similarly, create /GRNOD/PART set for the dummy collector and recall the same set in master_id of the interface.

Altair Forum User

Hi George,

I have created the INPUT condition as discussed earlier up to some extend as u advised to do.

The inlet is proper but there is some problem in the outlet.

The SPH particles which are present already in the tank were eliminated from the outlet boundary properly, but the newly created particles from inlet boundary were not eliminating (as shown in the animation).

20170613_125334.gif.87b884bb5e0fcc6a5ca1dfbfc7f71d2a.gif

Attaching the deck for reference.

Please suggest.

Thanking You.

ball_0000.rad

ball_0001.rad

Altair Forum User

Hi Pritam,

For the outlet also, similar to the inlet condition, select the contact surface of the outlet component and ensure that the element normals are also inwards towards the tank.

Please check these and try running the model.

Meanwhile in between I'll also review the model and will update soon.

Altair Forum User

Hi George,

All condition checked as u mentioned and all are in accordance as per your suggestion.

Still its not working.

Altair Forum User

HI Pritam,

I just tried in the model which I have sent before.

And the deck is attached along.

ball_0000_fd33b6fbe8cfdc9f4054e149ade4a093.rad

Altair Forum User

Hi George,

As you have done in the previous attachment, i tried with my model.

Some part is eliminating at the outlet properly, but some part are not (As in the animation below).

Unable to figure out the proper reason for it.

Please find the deck attached, if needed.

20170615_094919.gif.cbb4fde4611ef7390584be8c03861f4b.gif

nooutpr_0000.rad

nooutpr_0001.rad

Altair Forum User

Hi Pritam,

The methodology is same as before. Can you please recreate the outlet component and try running.

Altair Forum User

Hi George,

The problem regarding Inlet and Outlet is resolved.

I tried to create wave. I created a wave profile curve and assign it to loadcol IMPDISP to the 'water' component.

But after some time it is showing error.

The error is something like that.

Capture.JPG.865a746010b174eaed66b00147f2625f.JPG

Attaching the deck. Please suggest.

Thanking You.

wograv_impdips_0000.rad

wograv_impdips_0001.rad

Altair Forum User

I tried assigning that load collector to some of the existing sph nodes instead of the component.

The effect is only applied to the assigned nodes, but there is no effect on the new incoming nodes from inlet boundary.

20170618_125852.gif.472e6385c0b010fbfe47450cdb48098e.gif

Altair Forum User

Hi Pritam,

This null diameter error means that a particle is so much compressed that its diameter is zero which results in problems.

Most of the time, this is due to an input error. You can check the consistency between mass / density and diameter / particle pitch and material characteristics. And I also doubt on the loading conditions provided. I'll recheck on assigning loads to /SPH/INOUT particles and will let you know.

Altair Forum User

Hi George,

I tried the different alternate and variation with the different properties (i.e. mass, density,pitch etc. [I am unable to find out, what is diameter of sph particles is?], but nothing is working out. Some changes giving weird behavior.

I tried changing load collector also. But not getting the desired result.

Please suggest something.

Thanking You.

Altair Forum User

Hi Pritam,

As suggested before with the available generic loads available we cannot create wave. And we cannot impose loads to that particles generated through /SPH/INOUT method.

Only a workaround that i can suggest is, you can try creating cross pillar like structure in the tank and define an interface between the pillar and sph particles. This may help you to create a similar sloshing effect.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi George,

I am unable to find out, what is diameter of sph particles is?

Can you please specify, how to control diameter of sph particles.

Thanking You.

Altair Forum User

Hi Pritam,

This generally depends on h value. The diameter of the particles h is recalculated as a function of the density according to the relation rho * h = constant. I don't think any other factors could influence this variable.