Multiple blocks in Blockmesh problems - cfdemsolverIB

Dear all,

My problem is within combining multiple blocks within the CFD blockmesh (using uniform mesh cells), which results in a badly calculated void fraction.

For my problem I do not want to use a typical duct (1 block) but a cylinder (many blocks). In order to simulate such a geometry the cfdemsolverIB requires uniform cells. Combining multiple blocks in the BlockMesh can approximate a cylinder using uniform cells (see figure).

Part of the Blockmesh will then look like:

blocks
(
...
...
hex (739 738 737 736 743 742 741 740) ( 1 6 60) simpleGrading (1 1 1)
hex (747 746 745 744 751 750 749 748) ( 6 1 60) simpleGrading (1 1 1)
hex (755 754 753 752 759 758 757 756) ( 1 6 60) simpleGrading (1 1 1)
hex (763 762 761 760 767 766 765 764) ( 6 1 60) simpleGrading (1 1 1)
hex (771 770 769 768 775 774 773 772) ( 1 12 60) simpleGrading (1 1 1)
hex (779 778 777 776 783 782 781 780) ( 1 12 60) simpleGrading (1 1 1)
hex (787 786 785 784 791 790 789 788) ( 1 22 60) simpleGrading (1 1 1)
hex (795 794 793 792 799 798 797 796) ( 1 22 60) simpleGrading (1 1 1)
hex (803 802 801 800 807 806 805 804) ( 1 28 60) simpleGrading (1 1 1)
hex (811 810 809 808 815 814 813 812) ( 1 28 60) simpleGrading (1 1 1)
...
...
)

As you can see, many blocks are needed to well simulate both the internal mesh and the walls. However, now when using this mesh for the simulation, the void fraction is not well calculated (see figure) and is only calculated inside the "Block" of its center. Do you know whether this is a limitation of the cfdemSolverIB and would you perhaps know how to solve this?

Best,

Boris