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LaO3/2-GaO3/2-ZrO2 ternary glasses have been prepared by aerodynamic levitation technique. The highest refractive index of glass system is 1.976 and the Abbe number of glass system reaches 49.9 for 30LaO3/2-62.5GaO3/2-7.5ZrO2 glass. Glasses have high transmittance of over 80% from ultraviolet light to the middle infrared light region. The maximum of infrared cutoff wavelength reaches to 10.6 μm. After ZrO2 doping, the acid corrosion resistance of glass is increased and the hardness of glass is improved from 7.14 GPa to 7.72 GPa ZrO2 adding increases the transforming temperature and crystallization temperature of glasses and improves the thermal stability of the glasses. The proper amount of ZrO2 doping improves the corrosion resistance, hardness, thermal and optical properties of the glass at the same time, which indicates that LaO3/2-GaO3/2-ZrO2 ternary glasses may have the potential to be used in a variety of endoscopes, especially those that need to be used in harsh environments.

In the present study, a detailed assessment investigation of Very-Large Eddy Simulation (VLES) method is performed using the open-source toolbox OpenFOAM for the simulation of turbulent separated flow. The VLES method is a unified simulation approach enabling a seamless evolution from Reynolds-Averaged Navier-Stokes (RANS) to quasi Direct Numerical Simulation (quasi-DNS) depending on the numerical resolution. Two VLES models, i.e. VLES-k-e and VLES-k-ω, are implemented in OpenFOAM and applied in the present study. In order to assess the performance of VLES models based on the framework of OpenFOAM, four classic separated flow are selected and investigated in details, including the flow past a triangular bluff body at Re ​= ​45,000, the flow past a backward facing step at Re ​= ​40,000, the periodic hill flow at Re ​= ​10,595, and the flow past a circular cylinder at Re ​= ​41,300. The comparisons between VLES simulation results and experiments give an indication on the adequacy and accuracy of the VLES modelling method based on the OpenFOAM toolbox. The VLES-k-ω model performs slightly better than the VLES-k-e model on a relatively low mesh resolution, especially in predicting the turbulent separation flow induced by the pressure gradient on a smooth surface. The results also demonstrate the reliability and accuracy of the VLES modelling based on OpenFOAM platform for complex separated flow simulations.