Computational fluid-structure interaction study of the aeroelastic behavior of a wire in transonic and supersonic flows

Air flow is employed in many textile processes to transport or to excite yarns to move in specific directions. Air flows cannot be controlled completely, which leads to some deviations or unexpected behaviour of the guided objects like a yarn. In this research, the interaction between a yarn and the surrounding air flow is studied in two applications: yarn splicing and yarn weaving. Both applications involve compressible flow and it is found that the compressibility effects on the turbulence have to be taken into account. In the first application, yarn splicing is studied based on air flow simulations. The CFD results are linked to experiments and the best flow characteristics are determined. The second application focuses on the main nozzle, which is an essential part of an air jet weaving machine. The geometry of the main nozzle is optimized to give the highest axial aerodynamic force, thus the highest weft yarn speed. The motion of a weft yarn inside a main nozzle is modelled by coupling a 2D axisymmetric fluid model and 3D structure one. The effects of the yarn motion on the air flow are added by a source term to avoid the problems of employing a dynamic mesh which is proven to be complex with a flexible object like a yarn.