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The surface topography of oxide multilayer mirrors with Ion Beam Sputtering (IBS) technology is experimentally investigated by Atomic Force Microscope (AFM). Different film materials, substrates polishing and cleaning methods are experimented for promoting the mirrors quality, respectively. PSD (Power Spectral Density) characteristic of different substrates and films has been compared. Surface roughness with different polished methods has been analyzed too. The result shows that the depositional property of film materials determines the principal characteristic of mirror surface topography, and the substrate polishing and cleaning quality mostly affects the mirror optical quality.

Due to an ongoing trend of high injection pressures in the realm of internal combustion engines, the role of cavitation that typically happens inside the injector nozzle has become increasingly important. In this work, a large eddy simulation (LES) with cavitation modeled on the basis of an Eulerian Stochastic Field (ESF) method and a homogeneous mixture model is performed to investigate the role of cavitation on academic injector. The ESF cavitation model is coupled to a pressure based solver for the flow, which lowers the computational cost, thereby making the methodology highly applicable to realistic injector geometries. Moreover, the nature of the ESF method makes it more convenient to achieve a high scalability when applied to parallel cases, which gives the method an edge over cavitation models that are based on Lagrangian tracking. The result of the ESF simulation is compared against that from a typical single volume fraction solver for validation. The capability of the ESF model to capture the probability density function (PDF) of vapor bubble radii is also demonstrated.

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