温度、盐度和流体类型对圆柱周围湍流声学特性的影响研究

The effects of the temperature,salinity,and fluid type on the acoustic characteristics of turbulent flow around a circular cylinder were numerically investigated for the Reynolds numbers of 2.25×10^(4),4.5×10^(4),and 9.0×10^(4).Various hybrid methodsReynolds-averaged Navier-Stokes(BANS)with the Ffowcs Williams and Hawkings(FWH)model,detached-eddy simulation(DES)with FWH,and large-eddy simulation with FWH-were used for the acoustic analyses,and their performances were evaluated by comparing the predicted results with the experimental data.The DES-FWH hybrid method was found to be suitable for the aero-and hydro-acoustic analysis.The hydro-acoustic measurements were performed in a silent circulation channel for the Reynolds number of 2.25×10^(4).The results showed that the fluid temperature caused an increase in the overall sound pressure levels(OASPLs)and the maximum sound pressure levels(SPL_(T))for the air medium;however,it caused a decrease for the water medium.The salinity had smaller effects on the OASPL and SPLT compared to the temperature.Moreover,the main peak frequency increased with the air temperature but decreased with the water temperature,and it was nearly constant with the change in the salinity ratio.The SPLT and OASPL for the water medium were quite higher than those for the air medium.

蒙陕接壤区采煤对白垩系水资源的影响研究

为了弄清蒙陕接壤区采煤对白垩系水资源的影响,分别从安定组的岩性和结构特征、各含水层的水文地球化学特征及水力联系、地下水流数值模拟等方面开展了研究。结果表明:安定组地层以泥岩类为主,厚度较厚,分布连续,隔水性能较好;安定组顶与主采煤层之间厚度一般超过200m,主采煤层导水裂隙带发育高度则不超过148.8m,煤层开采不会波及白垩系地层。白垩系含水层与侏罗系含水层水化学特征差异显著,反映了上下含水层水力联系较差。随着煤炭持续开采,采空区面积逐渐增大,矿井涌水量从249.0m^3/h逐渐增加至994.0m^3/h,侏罗系水位下降了超过200m,白垩系和第四系水位则保持稳定。地下水流模拟预测发现,随着煤炭开采,10年后矿井涌水量将逐渐增加至1616.0m^3/h,并基本保持稳定;侏罗系含水层将逐渐形成一个大的降落漏斗,但受安定组隔水关键层作用,白垩系向安定组入渗水量只有矿井涌水量的9.1%,影响极小。总体上,蒙陕接壤区安定组隔水性能较好,阻隔了白垩系与侏罗系的水力联系,且在煤层开采过程中导水裂缝带未波及安定组,起到了隔水关键层作用,能够实现采动条件下对白垩系水资源的有效保护。