二维曲壁扩压器内湍流边界层分离的研究  

Investigation of Turbulent Separating Flow in a Curved-wall Diffuser

作　　者：丁万山[1] 尹军飞 

机构地区：[1]南京航空航天大学

出　　处：《应用力学学报》1994年第4期33-38,共6页Chinese Journal of Applied Mechanics

摘　　要：本文应用二维双色四光束激光多普勒测速仪和压强探针详细地测量了二维非对称曲面扩张通道内的不可压湍流边界层分离流动，得到了时均速度和雷诺剪应力以及正反向间歇流动因子和静压分布。实验结果分析表明：湍流边界层分离时，沿边界层高度方向存在着明显的压强差。压强差的极小值对应于位移厚度曲率的极大值和瞬时间歇分离点。Ｂａｒｄｉｎａ对数尾迹律可以较好地描述瞬时间歇分离点之前的边界层速度分布，但无法描述分离的边界层速度分布。A two-dimensional diffuser with a lower curved wall and upper flat plate is studied.There is aparallel channel connected with the exit of the diffuser.The turbulent boundary layer separates on thelower wall due to the strong adverse pressure gradient,and then the separated boundary layer reattach-es on the parallel channel.In the inlet of the diffuser,Reynolds number based on the inlet height ofthe channel is 10400 and based on the local boundary-layer momentum thickness is 4980 and the inletvelocity is 2 5.2m/s.A two-dimensional laser doppler velocimeter was employed to survey the flowfield.Mean velocity and Reynolds stresses were measured from upstream of the separation to thedownstream of the reattachment with 23 sections.Theminimum distance from the surfaceis 0.3mm. The wall pressure and static pressure profiles are presented. The result shows that the strong adversepressure gradient ,wall curvature and strcamline curvature play an important role in the separation. The analysis gives that cross-stream pressure gradient is signifieant in the separating flow. The maxi-mum of the displacement thickness curvature K_(max)corresponds to the intermittency transitory detach-ment(ITD)and to the minimum normal pressure difference. Sandborn&Kline′s separation criterion isnot suitable to the present flow due to indicate a smaller separating region than that in the experiment.several velocity profiles are compared with the experiment.Bardina′s velocity profile can fit the ex-perimental results well before ITD,but ean not fit those well in the detached flow,Cross′s velocityprofile can fit the experimental profiles well in the separated flow.

关 键 词：分离流 湍流 边界层 二维扩压器 空气动力学 

分 类 号：V211.18[航空宇航科学与技术—航空宇航推进理论与工程]