СЕКЦИОНИРОВАНИЕ НАБЕГАЮЩЕГО ПОТОКА ПРИ СВЕРХЗВУКОВОМ ПОПЕРЕЧНОМ ОБТЕКАНИИ КРУГОВОГО ЦИЛИНДРА

Abstract

The numerical simulation results of supersonic incident flow along a cross circular cylinder of different length in Mach number range from 2.5 up to 3.5 with Reynolds number Re= 2∙10 6 are presented in the article. Numerical simulation was carried out using unsteady three-dimensional Reynolds-averaged Navier–Stokes equations for compressible fluid. For the equation system closure four turbulence models such as SST (Shear Stress Transport), SAS SST (Scale-Adaptive Simulation Shear Stress Transport), DES (Detached Eddy Simulation) and LES (Large Eddy Simulation) were used. The numerical solution of the reference equations was obtained due to a control volume approach. In the calculations numerical methods that have the second order of approximation by space variables were used. The solution is presented to the task in three dimensional statement of flow around the infinite cylinder. Due to the results of the numerical modeling the availability of large-scale vortexes that bring to a sectioning of the incident flow was discovered. In process of streamlining the flow is divided into equal segments (sections) along the cylinder. Formed sections of the flow are structured along the cylinder and have the equal scale. The influence of the cylinder length on a sectioning scale and structure is considered. The numerical simulation results of the supersonic incident flow sectioning along a cross cylinder with the length 6d, 4d and 2d (where d is a diameter of current cylinder) are presented in the article. In this case the size of control volumes along the cylinder is constant. In addition Mach number influence on the sectioning scale and structure is considered. Mach number effect on origin and attenuation is done for the cylinder length 4d in Mach number range from 2.5 up to 3.5 with the constant Reynolds number. Also the causes of sectioning generating of the supersonic incident flow along the cross cylinder are discussed. The possible causes are space discontinuity of incident flow, flow instability in an area of the front critical point and interaction between the shock wave and vortex flow in a shock layer.