Effect of distributed gas injection on aerodynamic characteristics of a body of revolution in a supersonic flow

Results of experimental and numerical investigations of the effect of gas injection through a permeable porous surface on the drag coefficient of a cone-cylinder body of revolution in a supersonic flow with the Mach number range M _h = 3–6 are presented. It is demonstrated that gas injection through a porous nose cone with gas flow rates being 6–8% of the free-stream flow rate in the mid-section leads to a decrease in the drag coefficient approximately by 5–7%. The contributions of the decrease in the drag force acting on the model forebody and of the increase in the base pressure to the total drag reduction are approximately identical. Gas injection through a porous base surface with the flow rate approximately equal to 1% leads to a threefold increase in the base pressure and to a decrease in the drag coefficient. Gas injection through a porous base surface with the flow rate approximately equal to 5% gives rise to a supersonic flow zone in the base region.     

Aerodynamic characteristics of a body of revolution with gas-permeable surface areas

Results of experimental studies and numerical calculations of aerodynamic characteristics of a supersonic flow around a body of revolution with a gas-permeable porous nose cone and an internal duct are presented. At a flow velocity corresponding to the Mach number M = 3, the body considered is found to have a lower drag coefficient (approximately by 9%) than a similar body impermeable for the gas and a lower streamwise static stability.     

On the possible formation of a vortex flow in a supersonic inlet with three-dimensional compression

The structure of the flow in an inlet with three-dimensional compression and an adjoining channel of rectangular cross-section is experimentally investigated for the external flow parameters M_∞ = 4 and Re ≈ 52 · 10⁶ 1/m. The phenomenon of vortex generation in the air-intake and its breakdown at the channel entry, where it encounters an elevated pressure gradient, is studied     

Processes Proceeding in Fe–0.12C–1Cr–1Mo–1V Steel after Pressure Cycling

The evolution of the phase content and morphology and crystalline defects during temperature and pressure cycling is studied by the methods of transmission electron microscopy and x-ray diffraction analysis. Thermostable Fe–0.12C–1Cr–1Mo–1V steel in the initial ferrite-pearlite state is examined. The evolution of the grain structure and dislocation density is quantitatively described. A low stability of large pearlite grains at temperatures above 600°C is established. The problem of oxidizing of steel of this class is also discussed.     

Technique for experimental determination of the total thrust-aerodynamic characteristics of aircraft models

A method of experimental determination of the force characteristics of nozzles (thrust, lift, and pitching moment) simultaneously with the aerodynamic characteristics of an aircraft model in a supersonic flow in proposed. The tests were conducted for a special methodical model, with equilibrium of the thrust and drag jorces being reached. It is shown that the internal force characteristics of the nozzle and the drag of the model, as well as the effective lift and pitching moment (with account of propulsion), can be determined from the measured thrust of the propulsion simulator. Institute of Theoretical and Applied Mechanics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 6, pp. 73–82, November–December, 1999.