Large-eddy simulation: Past, present and the future

Large-eddy simulation（LES） was originally proposed for simulating atmospheric flows in the 1960 s and has become one of the most promising and successful methodology for simulating turbulent flows with the improvement of computing power. It is now feasible to simulate complex engineering flows using LES. However, apart from the computing power, significant challenges still remain for LES to reach a level of maturity that brings this approach to the mainstream of engineering and industrial computations. This paper will describe briefly LES formalism first, present a quick glance at its history, review its current state focusing mainly on its applications in transitional flows and gas turbine combustor flows, discuss some major modelling and numerical challenges/issues that we are facing now and in the near future, and finish with the concluding remarks.

Clinical outcomes with a newvdesign in multifocal intraocular lens:a pilot study

Purpose:To evaluate the clinical and visual outcomes,quality of near vision and the influence of photic phenomena in patients bilaterally implanted with a new Precizon Presbyopic multifocal intraocular lens(IOL).Methods:In this prospective consecutive case series,20 eyes of 10 patients were included(mean age 63.80±12.55 years).Uncorrected and corrected visual acuity(far,intermediate and near),subjective refraction,binocular defocus curve,contrast sensitivity(CSV-1000)and quality of vision and satisfaction questionnaires were measured.The follow-up was 12 months after surgery.Results:At 12 months after surgery,uncorrected distance visual acuity(UDVA)improved with surgery(P=0.001)with a value of 0.08±0.08 logMAR.Uncorrected near visual acuity(UNVA)was 0.22±0.12 logMAR and distance corrected near visual acuity(DCNVA)was 0.16±0.13 logMAR.Intermediate distance visual acuity(UIVA)was 0.22±0.10 logMAR.Contrast sensitivity outcomes were similar to normal population in photopic conditions and slightly reduced in mesopic conditions of lighting.Defocus curve showed that this multifocal iOL was able to provide a visual acuity(VA)equal to or better than 0.16 logMAR between defocus levels of+1.00 to-2.50 D.Good patient satisfaction was obtained in quality of vision and satisfaction questionnaires outcomes.Conclusions:The Precizon Presbyopic NVA IOL(OPHTEC BV)provides good visual outcomes.This multifocal IOL provides a high percentage of spectacle independence due to good VA at far,intermediate and near distances and satisfactory contrast sensitivity.High patient satisfaction was observed in quality of vision and satisfaction questionnaires with a low percentage of patients manifesting photic phenomena.

Clinical outcomes with a new design in multifocal intraocular lens:a pilot study

Purpose:To evaluate the clinical and visual outcomes,quality of near vision and the influence of photic phenomena in patients bilaterally implanted with a new Precizon Presbyopic multifocal intraocular lens(IOL).Methods:In this prospective consecutive case series,20 eyes of 10 patients were included(mean age 63.80±12.55 years).Uncorrected and corrected visual acuity(far,intermediate and near),subjective refraction,binocular defocus curve,contrast sensitivity(CSV-1000)and quality of vision and satisfaction questionnaires were measured.The follow-up was 12 months after surgery.Results:At 12 months after surgery,uncorrected distance visual acuity(UDVA)improved with surgery(p=0.001)with a value of 0.08±0.08 logMAR.Uncorrected near visual acuity(UNVA)was 0.22±0.12 logMAR and distance corrected near visual acuity(DCNVA)was 0.16±0.13 logMAR.Intermediate distance visual acuity(UIVA)was 0.22±0.10 logMAR.Contrast sensitivity outcomes were similar to normal population in photopic conditions and slightly reduced in mesopic conditions of lighting.Defocus curve showed that this multifocal IOL was able to provide a visual acuity(VA)equal or better to 0.16 logMAR between defocus levels of+1.00 to−2.50 D.Good patient satisfaction was obtained in quality of vision and satisfaction questionnaires outcomes.Conclusions:The Precizon Presbyopic NVA IOL(OPHTEC BV)provides good visual outcomes.This multifocal IOL provides a high percentage of spectacle independence due to good VA at far,intermediate and near distances and satisfactory contrast sensitivity.High patient satisfaction was observed in quality of vision and satisfaction questionnaires with a low percentage of patients manifesting photic phenomena.