The recent use of slippery surfaces such as super hydrophobic and liquid-infused surfaces have demonstrated remarkable properties in reducing flow separation around bluff and slender bodies, modifying the separation of the boundary layer and the dynamics of the recirculation region. However, designing strategies to reduce the noise radiated by the separated region remains an open question. When considering the noise radiated by propulsion systems, the origin of sound generation is generated by the incipient separation whose precursor events lead to massively separated flow regions. The latter has a solid unsteady nature and is at the origin of the radiated noise in the near wake. The ambition of the LOTUS project is to understand how slippery surfaces can allow for attenuating the noise radiated using a multidisciplinary multi-scale approach coupling laboratory experiments with high-fidelity numerical simulations. In particular, we propose a novel strategy for the design and optimisation of superhydrophobic and liquid-infused surfaces over a blade profile with the aim of controlling incipient separation to attenuate the sources of noise. The tasks of the project will be jointly performed by PRISME laboratory and ENSTA Paris whose experimental facilities will allow for exploring a large range of physical parameters associated with (i) incoming turbulence, (ii) slippery-interfaces' deformation, and (iii) cavitation regimes. The LOTUS project aims at designing a methodology capable of engineering and optimizing turbulent flows in complex geometries, by means of textured surfaces which either repel water or use different fluids at the interface. The goal of this work aims at demonstrating the feasibility of a passive-control method, based on a homogenization technique for the coupling between the slippery surface and the outer fluid, to attenuate the noise generated by turbulence as well as cavitation for submarine propellers. The project combines high-fidelity numerical simulations for the characterisation of the turbulent flow and an adjoint method to the simulation for the design of the slippery surfaces. In addition, an experimental characterisation in a cavitating tunnel will allow for assessing the performances and the durability of the newly engineered surfaces with an application on a propeller blade. This project, therefore, tackles several open scientific questions regarding the analysis and the design of slippery surfaces towards the passive control of hydroacoustics. The radiated noise will be modelled using Ligthill's analogy and the slippery surfaces' design will be dedicated to the optimal attenuation of the mechanisms leading to noise generation. In addition, the best designs will be tested in a cavitating water channel assessing the validity and durability of both super-hydrophobic and liquid-infused surfaces. The project is built around four tasks: (i) High-fidelity numerical simulations of turbulent flows in the presence of a pressure gradient over a deformable wall, representing a submarine propeller blade. (ii) The design of a slippery wall based on an adjoint procedure with the aim of attenuating noise generation mechanisms. (iii) The analysis of the sound generated over different optimised deformable slippery surfaces. (iv) Testing the best designs in a cavitating tunnel and applying the same principles to an actual propeller-blade model assessing both the performances and the durability of the approach.