# Moving Solid particle in a flow

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 July 6, 2009, 08:18 Moving Solid particle in a flow #1 New Member   yigit Join Date: Jul 2009 Posts: 4 Rep Power: 9 Hi everybody I m trying to model and analyse the behaviour of a solid particle (in a a7 paper size) in a wind tunnel with inlet velocity 180 km/h. does anybody make such an analyse? I want to see how solid material move and velocity behaviour of this material.. It would be nice if u have send me any information page or document...

 July 6, 2009, 10:54 #2 Senior Member     George Join Date: Mar 2009 Location: Birmingham, UK Posts: 257 Rep Power: 10 check the smoke tutorial __________________ Top 4 tips 1. Knowledge is everything and Ignorance is dangerous. 2. Understand your limitations and try to eliminate them. 3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window. 4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials

 July 6, 2009, 15:36 #3 New Member   yigit Join Date: Jul 2009 Posts: 4 Rep Power: 9 hi George thanks but how can i control the geometry and size, I mean my solid material is just like a coin (d:30mm t:1mm) What i want to do i place this coin in to the windtunnel so that its big lateral surface be parallel to the inlet flow and then in the second analyse perpendicular to flow to see how it moves under 180kmh inlet velocity..

 July 6, 2009, 16:47 #4 Senior Member     George Join Date: Mar 2009 Location: Birmingham, UK Posts: 257 Rep Power: 10 3 ways that i can think of all have its pros and cons a) it could be possible to use Lagrangian–Eulerian multiphase model and define the particle using shape factors. you need to check whenether you can model the coin shape using shape factors b) moving mesh... very very messy c) use the immersed solids in v12 however you will use a beta function and turbulence effects due are not calculated __________________ Top 4 tips 1. Knowledge is everything and Ignorance is dangerous. 2. Understand your limitations and try to eliminate them. 3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window. 4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials

 July 6, 2009, 22:23 #5 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,707 Rep Power: 98 Hi, Immersed solids is a fully released feature, not a beta feature. Also it does include turbulence effects but cannot accurately capture detailed boundary layer effects as it is very difficult to use a fine enough mesh to capture these effects. My first go would be to use the lagrangian particle tracking but that will not be very accurate as you won't be able to take into effect the fact the coin has very different drag forces depending on its orientation. The immersed body feature will be able to capture these effects but to get an accurate overall aerodynamic force on the coin will require a very fine mesh. A tricky simulation. Glenn Horrocks

 July 7, 2009, 06:53 #6 New Member   yigit Join Date: Jul 2009 Posts: 4 Rep Power: 9 In our university we use Ansys 11 so I cant concentrate on immersed body feature.. I will give a try to lagrangian particle tracking.. But can u tell me how to implement this feature? or any example just to understand the idea I never used it

 July 7, 2009, 07:50 #7 New Member   yigit Join Date: Jul 2009 Posts: 4 Rep Power: 9 Ok i found it... Thanks for the help...

 July 8, 2009, 22:21 #8 Senior Member   Michael P. Owen Join Date: Mar 2009 Posts: 196 Rep Power: 9 The relevant feature of R12 is not immersed solids but rather the 6DOF solver, which is in fact in beta. This problem can be attacked in v11 without resorting to FORTRAN. However, the techniques I developed for this are advanced, and become more complex the more degrees of freedom are allowed. Here is an example that illustrates some of the functionality that you would need: http://www.youtube.com/watch?v=md8vXAUn7g0 This could be extended to allow translations in addition to rotation about a single axis, but allowing arbitrary rotations is probably not feasible (although I haven't tried to develop a full 6DOF technique for v11; so maybe it can be done).

July 9, 2009, 02:54
#9
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George
Join Date: Mar 2009
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Quote:
 Originally Posted by michael_owen The relevant feature of R12 is not immersed solids but rather the 6DOF solver, which is in fact in beta. This problem can be attacked in v11 without resorting to FORTRAN. However, the techniques I developed for this are advanced, and become more complex the more degrees of freedom are allowed. Here is an example that illustrates some of the functionality that you would need: http://www.youtube.com/watch?v=md8vXAUn7g0 This could be extended to allow translations in addition to rotation about a single axis, but allowing arbitrary rotations is probably not feasible (although I haven't tried to develop a full 6DOF technique for v11; so maybe it can be done).
cool videos mate
__________________
Top 4 tips
1. Knowledge is everything and Ignorance is dangerous.
2. Understand your limitations and try to eliminate them.
3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window.
4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials

 July 9, 2009, 07:04 #10 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,707 Rep Power: 98 Hi, Yes, you are right. The immersed solids is a full release feature in V12 but linking it to a 6DOF solver is beta. Some nice videos on your youtube site Micheal. The bullet in the tube is especially cool. Glenn Horrocks

 July 9, 2009, 08:58 #11 Senior Member   Michael P. Owen Join Date: Mar 2009 Posts: 196 Rep Power: 9 RE: that video, with all the threads/questions about the Riemann problem/shock tubes, I'm surprised I haven't seen anyone mention PPM.

 July 9, 2009, 18:36 #12 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,707 Rep Power: 98 PPM? What's that?

 July 14, 2009, 08:30 Mechovator #13 Member   mechovator Join Date: May 2009 Posts: 32 Rep Power: 9 PPM means part per million. like sand suspended in water is measured with PPM.

July 14, 2009, 08:48
#14
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Join Date: Mar 2009
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Quote:
 Originally Posted by mechovator PPM means part per million. like sand suspended in water is measured with PPM.
Not untrue, but somewhat out of context. Piecewise parabolic method might be a better guess here.

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