喷管出口处初始湍流结构对自由射流渐近扩张速率的影响

EFFECTS OF INITIAL TURBULENCE STRUCTURE AT NOZZLE OUTLET TO THE ASYMPTOTIC SPREADING RATE OF FREE JETS

喷管出口处初始湍流结构对自由射流渐近扩张速率的影响吕盘明（中国科技大学热科学和能源工程系合肥２３００２６）关键词自由射流；边界条件；湍流模型；湍流结构１引言关于标准的ｋ－εＥＶＭ（涡粘性模型）的通用性有三个最最典型的疑难例子（或者说是佯谬）在很多文献...

It has been noted from available experimental data that the asymptotic spreading rates of the free jets, both planar and axisymmetric, were dependent upon the initial conditions. So the in-rbulence models should be able to include the effects of upstream boundary conditions of turbulence structure.The present computations showed that the linear anisotropic k-E LAEVM do have demonstrated such ability. In addition to this,considering the turbuleflt variables of the free jet was only self-preserving beyond x/d >40 and 70(where d is the diameter of the nozzle), respectively,for plane jet and round jet,the computation domain should be at least larger than this area.If not,the spreading rate of the round jet may be seriously overpredicted.It has longly been believed that the spreading rate of the round jet may be overpredicted 40%, i.e.0.125 to the data 0.086, using the standard isotropic turbulence model k-E EVM etc.,in contrast to it,the present paper showed that the calculation result, using the same model k-E EVM,is right around 0.088.