POLYFLOW  How to define an inverse prediction case for multiple extrudates (multihole profile)?
Let us consider a die with several holes, fed from one single channel that distributes the melt through the holes. Is it possible to perform an inverse extrusion simulation where the various independent die lips are simultaneously predicted? It is indeed possible. The topology should involve several subdomains, while the simulation should be defined with various subtasks, involving the same material, of course. Let us consider a Yshape channel, where the melt enters at the bottom and leaves at both upper exits; let us assume that die lips have to be designed for both exits. A first subtask shuold be defined on the lower part of the channel that should already involve the bifurcation. Two additional subtasks should be defined, respectively on the left and righthand side channels, with appropriate boundary conditions and attributes for inverse prediction. These two subtasks should be connected to the first one by means of fixed interfaces. This is a key issue to address this question.Let us consider a treeshaped channel, where the melt enters at the bottom and leaves at upper exits. The figure below shows a typical geometry, where both symmetry planes have been considered. <a target=_blank href="http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__topology.jpg">http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__topology.jpg</a>http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__topology.jpg Let us assume that die lips have to be designed for all exits. A first subtask shuold be defined on the green part of the channel t. Additional subtasks should be defined on triplets of (yellow,blue,red) regions, with appropriate boundary conditions and attributes for inverse prediction. The free jets are defined under the red subdomains, constant sections and adaptive sections for inverse predictions are respectively defined under the blue and yellow subdomains. These several subtasks shuld be connected to the first one by means of fixed interfaces. This is a key issue to address this question. A typical solution in shown on the figure below. <a target=_blank href="http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__result.jpg">http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__result.jpg</a>http://www.fluentusers.com/support/solutions/1368/multi_inv_extr__result.jpg 

