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Can you upload the simulation somewhere?

did you create an interface between the water and the air ?

Hello

Sergey Valerievich Anpilov ... i do not understand your answer

@Ahmed Beniaiche, do i need to create an interface between the water and the Air? I thought the only interface that we need to create was the one between the Overmesh and the Background....and i did that .

Based on my experience with Ansys fluent it is necessary to get an interface between the different fluids air and water. I will try during the day sending you a similar detailed work but on Ansys fluent. The interface insures that the deformation of the one volume will be considered within the second one so the conservation of quantities is insured .

hi Nankam Brice

1-Which version of star do you use?

2-Over-set mesh interpolate between Overlap and the Over-set parts to refine mesh during the simulation. because of that, where star ccm can't interpolate right , you will have some holes in mesh during the simulation.

3-Why didn't use morphing mesh or rotation & translation mesh? This mashers hasn't this problem and you can use symmetry plane.

4- are you read and do star example in this subject?(#boat_in_head_wave)

best rigards

hi Mohammad Hossein Rasti

1- I use the version V13.02

2-I have some update about my problem

i did read the example in the Tutorials about "Boat_In_Head_Waves"

When i realise the derived plan at Y=0 in that simulation to see how the mesh is, the plan mesh is "fine" without holes. I do not understand why....because someone tell me that i shouldn't do the cut at the symmetry plane ; it will cause some problem.

Now..do you know the Add in StarCCm that we call EHP?

Look, i take a boat , i realise a simulation with EHP, and since i'am interested how the mesh look like at the plane Y=0, i do realised a cut at that plan (Y=0). and guess what.! It appears with Holes!! So maybe i shouldn't realize the cut at this plan..

But why in the tutorials in star CCm, when i realise these cut, at Y=0, i do not have this holes? (What tricks have they done with their Geometry/simulations?).

3-Also...my other problem is that..when i realised the simulation with the half of my boat, it crashes every time...but when i do it with the entire boat (i mean all the instructions are same only that i use the entire boat) the simulation goes fine ( but i guess it need more time and i don't want that). So..i'am lost!

hi Nankam Brice

I'm glad to hear that you did this simulation even with entire boat. if in your simulation there isn't any impact , fall down or slamming i recommend morphing mesh for half boat.

About EHP. Unfortunately in our region it isn't accessible. however we simulate using common star tools instead of EHP and decrease run time.

in the official tutorial presented with star they aren't build meshes automatically.

best regards

hello Mohammad Hossein Rasti

thank you for you answer.

I will try the morphing mesh although i never try it yet.

You said , you use another tricks to decrease the running time....could you advice some methods to me please?

Also, what do you means by saying that the meshes aren't build automatically in the tutorials?

Hi Nankam Brice

In star tutorials they generate mesh region, node by node. star has direct mesh methods and can import mesh from other meshing programs.I think they aren't generated meshes in star and import mesh from other program or mesh node by node.

if in simulation mesh use curvature control and surface control you can decrease number of cells and decrease time run. do refining free surface similar than KCS example. for increase accuracy use hyperbolic tangent prism layer mesh. then without reducing accuracy you can decrease mesh in far from body.

other trick is use field function meshes. i still newcomer in this trick.

Hi Nankam Brice

In some last days, I saw a similar error in a star with regular mesh without motion and saw convergence error in the output window. are you saw this error?

Best Regards

Hi every one

im making a simulation of an object moving by flowing water into a tank it would be great if you could send me a related tutorial ?

thanks

hi Mohammad Hossein Rasti ....have you found the answer to your problem?

I can't see clearly what you are trying to show.

Can you explain it again if you haven't found the solution yet..?

HelloTarek Shaheen

What do you want exactlly to simulate?

An oject moving in water (Water in a tank) or something else?

thank you very much for your answer yes exactly I want to simulate the movement of a body, which was created because of the waters force