Development of a spectral method code for simulating liquid films instabilities in hot dip galvanisation

Hot dip galvanisation is an industrial process of coating iron and steel in zinc. The process can be optimised with the usage of gas actuators which can reduce the thickness, therefore the zinc used is less and the cost is reduced, meanwhile improving the homogeneity of the final coating. This cost-effective technique is known as jet wiping and it is widely used in industrial processes. However the interaction between the gas accelerated by the jet and the liquid film produces a wavy final coating films. The aim of the research team of the Von Karman Institute, in collaboration with ArcelorMittal, is the development of the BLEW (Boundary LayEr Wiping) software to predict the liquid films dynamic. The aim of this work is to keep improving the BLEW solver introducing a spectral method needed to reduce the computational time and numerical diffusion. This thesis presents the spectral method, introduces different examples used to understand the ins and outs of the scheme and finally shows the application to the real case study.