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Old   July 14, 2008, 16:25
Default star ccm 3.04
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jecil
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does anyone knows what of these (langrangian, eulerian, vof ) does the new version of star ccmm has????

thanks in advance
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Old   July 15, 2008, 03:15
Default Re: star ccm 3.04
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NaMe
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all of them..
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Old   July 15, 2008, 07:16
Default Re: star ccm 3.04
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jecil
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hello

so you mean that i can make a these simulations:

tank filling (a tank that we fill with gasoline) dynamic fluid body interaction ( a missile that runs and the air chance his target, can we make also moving flaps?)

thanks a lot
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Old   July 15, 2008, 08:16
Default Re: star ccm 3.04
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jecil
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also can we have more than 1 solid parts and apply contacts between of them??? like flow 3d

thanks
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Old   July 15, 2008, 08:22
Default Re: star ccm 3.04
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Louis
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Based o what I intepret from the press release, it can do 6DOF and prescribed motion moving mesh problems but is limited to cases where the mesh is rigid. So only a single body appears to be allowed currently. An isolated flap can be handled. But, a flap attached to a wing cannot be handled because it would require relative motion between parts of the mesh (one attached to the main element of the wing and the other to the flap). Unless they use overset meshes, which they don't mention.

If I am right, the press release is misleading because Jean-Claude Ercolanelli states "The meshing process for a DFBI simulation is identical to that for a simple non-moving calculation and the DFBI model accomplishes its task without invoking the complex and time-consuming re-meshing schemes used by other CFD tools." Yet below this quote the release goes on to say "... the DFBI model works by translating and rotating the entire computational domain in response to the fluid induced load"

This seems to limit the capability to single body motion. Comments are made as to how easy it is to use this feature. But it appears to me that the code is only capable of handling easy problems. More complex models will require more complex setup.

Don't get me wrong. I think CCM+ is the best option out there and that this new capablility is a big enhancement. I just think it is being oversold. Someone set me straight if I am wrong.

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Old   July 15, 2008, 17:55
Default Re: star ccm 3.04
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Stephen
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"If I am right, the press release is misleading because..."

Remeshing (in which the topology of the mesh changes) is fundamentally different from translating and rotating the mesh. The former is computationally expensive (and difficult to achieve in a robust and accurate manner), the latter is entirely robust and relatively inexpensive.

"the code is only capable of handling easy problems"

Since when did simulating the motion of a floating body under large amplitude excitation become an easy problem?

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Old   July 16, 2008, 01:17
Default Re: star ccm 3.04
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jecil
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well the ship simulations became easy problems today.... i saw the demo in the cd adapco website and i understad that the people did very good job, you just have to put high and peirod of the wave !!! and not spent time for boundaries, but .... these capabilities must go in the market after some other thing... like combustion with moving mesh etc, it would be god for everyone to have someone from cd adapco to solve our inguires on the new solver,

the problem that i have is to choose a code between star ccm and flow 3d fr my company, flow 3d has many great thing on 6 dof like the collision detection between the solid parts and also very good free surface modul.

so if anyone have any information if the star ccm is egual to flow 3d please inform me.

thanks
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Old   July 16, 2008, 07:35
Default Re: star ccm 3.04
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Louis
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"Remeshing (in which the topology of the mesh changes) is fundamentally different from translating and rotating the mesh. The former is computationally expensive (and difficult to achieve in a robust and accurate manner), the latter is entirely robust and relatively inexpensive."

Yes, but the latter cannot handle problems nearly as complicated as the former can handle (i.e. bodies in relative motion).

"Since when did simulating the motion of a floating body under large amplitude excitation become an easy problem?"

You are trying to deflect the discussion. Ship seakeeping simulations are not easy and star does appear to get good results. However, what is shining here is the VOF implementation. The mesh motion and 6DOF capability required to do these simulations is just shy of trivial (unless the mesh is adapting so that the free surface remains resolved as the grid moves, which I don't think it is).

While I think the new capability is useful, it is not as general as other implementations and is being oversold.
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Old   July 16, 2008, 07:40
Default Re: star ccm 3.04
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jecil
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i id not understand you.... can you be more accurate?
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Old   July 16, 2008, 08:17
Default Re: star ccm 3.04
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Louis
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I'm not sure what you are asking me to clarify. But, if your simulation requires the motion of one component relative to another, such as a bomb dropping from an aircraft or a car passing another car (or anything that requires the mesh to distort rather than just move as a rigid body) then I do not believe ccm+ can handle it (based only on what I read in the press release). However, star 4 should be able to.
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Old   July 17, 2008, 04:53
Default Re: star ccm 3.04
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jecil
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now i understand you, i want to simulate a missile that change the positions of the flaps when the air direction change so that will keep the same target. so i need the flaps to move (rotate ) on the missile shell with some sensors.

un fortunately i do not know anything n star cd to do this.
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Old   July 27, 2008, 23:41
Default Re: star ccm 3.04 *NM*
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M.B3
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