How to output user defined variable to the vtu file?

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raback
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Re: How to output user defined variable to the vtu file?

Post by raback » 08 Sep 2017, 18:56

Hi

Elemental fields are not constant here. Within each element there is a different value at each node. So this is as in "discontinuous galerkin" method. This way the code can in principle maintain some accuracy when using higher order edge elements. Of course for lowest order edge elements the \curl of the vector field is more or less constant within element so the only purpose of the elemental DG field is that it maintains the discontinuity of the data.

-Peter

Jenwel
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Re: How to output user defined variable to the vtu file?

Post by Jenwel » 09 Sep 2017, 09:17

Hi, Peter

Thank you so much for the answers! I understand now!

I revised the code as:

Code: Select all

DO i = 1, GetNOFActive()
		Element => GetActiveElement(i)
		Bnode1 = sqrt(EL_MFD % Values(EPerm(Element % DGIndexes(1)) * 3 - 2)**2 + &
		EL_MFD % Values(EPerm(Element % DGIndexes(1)) * 3 - 1)**2)
		Bnode2 = sqrt(EL_MFD % Values(EPerm(Element % DGIndexes(2)) * 3 - 2)**2 + &
		EL_MFD % Values(EPerm(Element % DGIndexes(2)) * 3 - 1)**2)
		Bnode3 = sqrt(EL_MFD % Values(EPerm(Element % DGIndexes(3)) * 3 - 2)**2 + &
		EL_MFD % Values(EPerm(Element % DGIndexes(3)) * 3 - 1)**2)
		! Find Constants
		Hc = GetConstReal(Model % Constants, "Hc", Found)
		IF(.NOT.Found) CALL Fatal("CoreLossSolver", "Unable to find Hc")
		Kh = GetConstReal(Model % Constants, "Kh", Found)
		IF(.NOT.Found) CALL Fatal("CoreLossSolver", "Unable to find Kh")
		Keddy = GetConstReal(Model % Constants, "Keddy", Found)
		IF(.NOT.Found) CALL Fatal("CoreLossSolver", "Unable to find Keddy")
	 IF (CurrentTimeStep>1) THEN
		IF ((Element % BodyId == 19) .OR. (Element % BodyId == 21)) THEN

			dB = Bnode1 - PrevB_E(EPerm(Element % DGIndexes(1)))
			PrevB_E(EPerm(Element % DGIndexes(1))) = Bnode1
			Phys_E % Values(EPerm(Element % DGIndexes(1))) = Hc * ABS(dB/dt) + Kh * Babs * ABS(dB/dt)
			Peddy_E % Values(EPerm(Element % DGIndexes(1))) = Keddy * (dB/dt)**2
			Pcoreloss_E % Values(EPerm(Element % DGIndexes(1))) = Phys_E % Values(EPerm(Element % DGIndexes(1))) +&
			 Peddy_E % Values(EPerm(Element % DGIndexes(1)))

			dB = Bnode2 - PrevB_E(EPerm(Element % DGIndexes(2)))
			PrevB_E(EPerm(Element % DGIndexes(2))) = Bnode2
			Phys_E % Values(EPerm(Element % DGIndexes(2))) = Hc * ABS(dB/dt) + Kh * Babs * ABS(dB/dt)
			Peddy_E % Values(EPerm(Element % DGIndexes(2))) = Keddy * (dB/dt)**2
			Pcoreloss_E % Values(EPerm(Element % DGIndexes(2))) = Phys_E % Values(EPerm(Element % DGIndexes(2))) +&
			 Peddy_E % Values(EPerm(Element % DGIndexes(2)))

			dB = Bnode3 - PrevB_E(EPerm(Element % DGIndexes(3)))
			PrevB_E(EPerm(Element % DGIndexes(3))) = Bnode3
			Phys_E % Values(EPerm(Element % DGIndexes(3))) = Hc * ABS(dB/dt) + Kh * Babs * ABS(dB/dt)
			Peddy_E % Values(EPerm(Element % DGIndexes(3))) = Keddy * (dB/dt)**2
			Pcoreloss_E % Values(EPerm(Element % DGIndexes(3))) = Phys_E % Values(EPerm(Element % DGIndexes(3))) +&
			 Peddy_E % Values(EPerm(Element % DGIndexes(3)))
		END IF
	 END IF
END DO 
Now only the transient loss of elements belong to electrical steel are solved, as shown in the following figures.
CoreLoss_ElementField.jpg
CoreLoss_ElementField
(119.26 KiB) Not downloaded yet
Fig 01
CoreLoss_ElementField_AirGap.jpg
CoreLoss_ElementField_AirGap
(137.95 KiB) Not downloaded yet
Fig 02

Fig02 shows that the core loss in the air gap has been removed.

Now I would continue multiplying the core loss per volume with the area of each element.

Thank you again!

BR
Jenwel

Jenwel
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Re: How to output user defined variable to the vtu file?

Post by Jenwel » 15 Sep 2017, 16:15

Hi, Peter

I want to ask that how can I obtain the area of each element in "CalcFields.F90"? Is there a variable that denotes the area of the element, in m^2 for the 2-D element?

Thank you in advance!

BR
Jenwel

raback
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Re: How to output user defined variable to the vtu file?

Post by raback » 15 Sep 2017, 17:10

Hi

The total Joule heating calculate below illustrates how to integrate over the mesh:

Code: Select all

Loop over elements
  Loop over integration points
       s = IP % s(j) * detJ
       ! The Joule heating power per unit volume: J.E = (sigma * E).E
       Coeff = SUM( MATMUL( REAL(CMat_ip(1:3,1:3)), TRANSPOSE(E(1:1,1:3)) ) * &
                   TRANSPOSE(E(1:1,1:3)) ) * Basis(p) * s
       Power = Power + Coeff
So the contribution in each Gaussian integration point is multiplied by the value of Basis function and integration weight times the element metric detJ. For linear element detJ is the area/volume of the element. This code was taken from CalcFields routine where you can see these lines in context.

-Peter

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