interDyMFoam for 2D cases

SD@TUB · January 26, 2011, 05:11

Dear FOAMers:

I am very pleased about the capabilities of the interDyMFoam solver released with version 1.7.x! Deriving the floatingObject tutorial i want to simulate 2D cases, which should be performed w/o any major difficulties. But i am stuck setting values in the pointDisplacement file as initial condition. The quantities of the needed values are related to 3D, like mass, moments of inertia, etc. What is to do when i have a 2D mesh (with one cell in the third cartesian direction, patch type empty as supposed to)?

Thanks in advance for helpful clues!

/Stefan

sleepdeprivation · February 1, 2011, 10:23

Since you have a 3D mesh, so you have an extrusion distance that you have to scale these 2D values by.
Eg, for Drag(2D) = Drag(3d)/L, scaled by L. (Watch Units.)

SD@TUB · February 3, 2011, 06:26

Thanks,

your explanation make sense indeed, but practically scaling the values within the pointDisplacement dict by extrusion length L yields no success.
Did you run simulations of e.g. an 2D airfoil with mesh motion technique, because you mentioned drag?

/Stefan

sleepdeprivation · February 3, 2011, 08:18

I actually had that problem with the forces function. Hence drag.

On mesh motions, I've used more solidBodyMotionFunctions, which are defined a little differently.
If you're using the sixDoFRigidBodyDisplacement function from the floating object tutorial for a 2D mesh, you may need constraints, but that's something I've never worked with. In solidBodyMotionFunctions there's a 3DoF and a 6Dof model.

January 26, 2011, 05:11	interDyMFoam for 2D cases	#1
SD@TUB Member Stefan Join Date: Jan 2010 Location: Kiel, Germany Posts: 81 Rep Power: 16	Dear FOAMers: I am very pleased about the capabilities of the interDyMFoam solver released with version 1.7.x! Deriving the floatingObject tutorial i want to simulate 2D cases, which should be performed w/o any major difficulties. But i am stuck setting values in the pointDisplacement file as initial condition. The quantities of the needed values are related to 3D, like mass, moments of inertia, etc. What is to do when i have a 2D mesh (with one cell in the third cartesian direction, patch type empty as supposed to)? Thanks in advance for helpful clues! /Stefan

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February 1, 2011, 10:23		#2
sleepdeprivation New Member Alton Luder III Join Date: Oct 2009 Location: Michigan Posts: 22 Rep Power: 17	Since you have a 3D mesh, so you have an extrusion distance that you have to scale these 2D values by. Eg, for Drag(2D) = Drag(3d)/L, scaled by L. (Watch Units.)

February 3, 2011, 06:26		#3
SD@TUB Member Stefan Join Date: Jan 2010 Location: Kiel, Germany Posts: 81 Rep Power: 16	Thanks, your explanation make sense indeed, but practically scaling the values within the pointDisplacement dict by extrusion length L yields no success. Did you run simulations of e.g. an 2D airfoil with mesh motion technique, because you mentioned drag? /Stefan

February 3, 2011, 08:18		#4
sleepdeprivation New Member Alton Luder III Join Date: Oct 2009 Location: Michigan Posts: 22 Rep Power: 17	I actually had that problem with the forces function. Hence drag. On mesh motions, I've used more solidBodyMotionFunctions, which are defined a little differently. If you're using the sixDoFRigidBodyDisplacement function from the floating object tutorial for a 2D mesh, you may need constraints, but that's something I've never worked with. In solidBodyMotionFunctions there's a 3DoF and a 6Dof model.