| Abstract: | The effect of external turbulence on the boundary layer flow in a convergent-divergent nozzle with a high expansion ratio has been studied numerically. The external turbulence was simulated by the turbulent viscosity  e, for which we used the partial differential equation that serves to close the system of boundary layer equations 1–4]. It was found that there exists a critical value cr such that for all e< cr the flow regime in the nozzle remains perfectly laminar, whereas for e cr a laminar-turbulent transition takes place and the boundary layer in the supersonic part of the nozzle becomes turbulent. For postcritical values of e the heat fluxes and friction losses are approximately an order greater than for precritical values. With increase in the Reynolds number, determined from the parameters in the nozzle throat, the value of cr decreases; as the coordinate of the onset of boundary layer formation is displaced in the direction of flow the value of cr increases.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 34–37, January–February, 1906.The authors are grateful to L. V. Gogish for participating in the discussion of the results. |
