The studies also show that maximum Mach number in the local supersonic region is not a unique factor influencing the separation, and the separation in transonic flows can occur at the incidence of 0o . For the calculation of viscous transonic flows, we use Fluent software with serious treatment of application operation based on the physical nature of phenomenon and the technique of numerical treatment. For the calculation of invicid transonic flows, we built a code solving the full potential equation with verification for accuracy. | Vietnam Journal of Mechanics, VAST, Vol. 33, No. 3 (2011), pp. 170 – 181 STUDY OF SEPARATION PHENOMENON IN TRANSONIC FLOWS PRODUCED BY INTERACTION BETWEEN SHOCK WAVE AND BOUNDARY LAYER Hoang Thi Bich Ngoc, Nguyen Manh Hung Hanoi University of Technology Abstract. For compressible flows, the transonic state depends on the geometry, Mach number and the incidence. This effect can produce shock wave. Some studies showed that the interaction between shock wave and boundary layer concerns separation phenomenon. Studies in this report demonstrate conditions of separation in transonic flow and that it is not any interaction between shock wave and boundary layer which can cause boundary layer separation. The studies also show that maximum Mach number in the local supersonic region is not a unique factor influencing the separation, and the separation in transonic flows can occur at the incidence of 0o . For the calculation of viscous transonic flows, we use Fluent software with serious treatment of application operation based on the physical nature of phenomenon and the technique of numerical treatment. For the calculation of invicid transonic flows, we built a code solving the full potential equation with verification for accuracy. Results calculated from Fluent have been seriously compared with results of present program and published results in order to assure the accuracy of application operation in the domain of investigation. Key words: Separation in transonic flows, shock wave and boundary layer. 1. INTRODUCTION For incompressible flows, the laminar flow regime is very sensitive to boundary layer separation. Our experimental study [1], [8] showed that the laminar separation has appeared at very small incidence, at 2o or 3o for profiles Naca 4412 and Naca 0012. Figure 1 presents experimental results in comparison with computational simulation on laminar separation for profile Naca 4412 with the incidence of and Reynolds number Re = 13000. In the turbulent .
