横流中紊流射流的三维数值模拟

Three-dimensional simulations of turbulence jets in cross-flow

从空间平均的非恒定三维不可压缩Navier-Stockes方程出发,采用Smagorinsky涡粘性模型模拟湍流,对横流中的射流进行了数值模拟.数值计算中采用了原始变量法,偏微分方程组的空间离散采用Galerkin有限元法,时间离散则采用半隐式.结合水槽实验,对比分析了无浮力和存在浮力两种流动情况下的射流流速场、射流轨迹线以及轨迹线上的流速.计算结果与PIV的实测流场比较表明,计算基本反映了实际的射流流动特点.计算与PIV实测流场得到的射流轨迹线基本一致,轨迹线上的流速两者相差一般在5%左右.

Numerical simulations are carried out to calculate turbulence jets in cross-flow. The mathematical model is based on spatial-filtered three-dimensional time dependent incompressible Navier- Stockes equations by using Smagorinsky sub-grid scale model. The calculation used the primary variable, Galerkin finite element method in space and semi-implicit scheme in time. Jets with and without buoyant force are modeled and compared with the velocity field obtained from PIV. The flow pattern and the jet trajectory from the simulation agree with that from the experiment. The difference of the velocity on the jet trajectory from the calculation and experiment is about 5%.