The project is focused on the development and validation of numerical models which are able to predict how suspended fibres orient themselves in various flow fields and also how the fibres and their orientation affect the flow field they are in. A statistical approach will be used for the theoretical description of the fibre orientation, where a continuity equation for the fibres in physical and orientation space is solved numerically. For the experimental part, methods developed at KTH Mechanics will be used to detect the fibre orientation by processing images of the fibre suspension. Two cases will be studied. The first is fibre orientation in shear flow of a suspension settling onto a solid wall. The second case considers settling of fibres in the same direction as the flow. A columnar local inhomogeneity of the orientation vector distribution will result in an averaged horizontal component of the settling speed. Fibres settling towards the same column from opposite directions will form a spatial inhomogeneity in fibre concentration which then generates the shear flow of the suspension. In the paper industry there is a need of predicting the fibre orientation in a paper machine since it strongly influences the material properties of the final paper. The development of statistical methods to deal with the orientation of fibres may be used for simultaneous implementation together with numerical codes for Computational Fluid Dynamics. The research will be run as a PhDstudent project with two assisting/supervising senior researchers.
Period: 20090101
 20111231
Keywords:
Fibre orientation, Fluid mechanics, FokkerPlanck, Paper technology, Shear flow


Proposed experimental setup. The piston to the right will be used to create a welldefined shear in space and time in the channel to the left. A camera will capture images of the fibres and analysis of the images will provide the fibre orientation distribution.

