超声速钝体逆向喷流减阻的数值模拟研究

Numerical investigation on counter-flow jet drag reduction of a bluff body in supersonic flow

为研究逆向喷流技术对超声速钝体减阻的影响,采用标准k-ε湍流模型,通过求解二维Navier-Stokes方程对超声速球头体逆向冷喷流流场进行了数值模拟,并着重分析了喷口总压、喷口尺寸对流场模态和减阻效果的影响。计算结果显示:随着喷流总压的变化,流场可出现两种流动模态,即长射流穿透模态和短射流穿透模态;喷流能使球头体受到的阻力明显减小;存在最大减阻临界喷流总压值(在所研究参数范围内最大减阻可达51.1%);在其它喷流物理参数不变时,随着喷口尺寸的增大,同一流动模态下的减阻效果下降。本文的研究对超声速钝体减阻技术在工程上的应用具有一定的参考价值。

To investigate the application of counter-flow jet technology to supersonic bluff body for drag reduction,the mixing flow field around a bluff body with a counter-flow jet from its front stagnation point in supersonic flow is numerically studied by solving the Navier-Stokes equation coupled with standard k-.turbulence model using the Van Leer’s flux vector splitting spatial discretion scheme.The Drag reduction and flow field affected by the jet total pressure and jet exit size are systematically investigated.It is found that there exist two flow modes in the mixing flow field.One is long penetration mode;the other is short penetration mode.The drag on the bluff body with counter-flow jet is reduced obviously.With other jet parameters fixed,a critical value of jet total pressure exists at which an optimal drag reduction can be obtained.,it is also found that the maximum drag reduction can reach as high as 51.1% for the cases studied.Fixing the jet physical parameter,with the increase of jet exit size,drag reduction effect is reduced under the same flow mode.The results may provide some useful information for the engineering application of supersonic blunt body drag reduction technology.