Numerical Simulation of Separated Flow over Flexible Structural Membranes

This research project aims to study large displacement fluid-structure interaction (FSI) problems through the development of a computational FSI code. The Navier-Stokes equations describing the behaviour of a viscous Newtonian fluid are discretised on a moving unstructured triangular mesh using the Finite Volume method. In two-dimensions the membrane structure is represented by a continuous array of one-dimensional line segments which are a subset of the fluid mesh edges. The fluid mesh remains attached to the membrane as it deforms, and the connectivity of the mesh remains constant throughout the simulation. The fluids equations are formulated in collocated primitive variable form, and the SIMPLE algorithm is used for velocity-pressure coupling. The Rhie-Chow interpolation is used for face mass fluxes to avoid spurious oscillations, and the non-orthogonality of the mesh is taken into account. The motion of the membrane structure nodes is calculated following the Dynamic Relaxation approach. The motion of the remaining mesh nodes is calculated following a structural spring analogy. Initial development has formulated the steady cases of flow past a normal flat plate and flow past a cylinder, and the unsteady case of flow past a cylinder with vortex shedding to validate the approach. Flow past a normal flat plate has been simulated on an arbitrarily moving mesh to validate the initial model in comparison with analysis on a stationary mesh