Viscosity effects on weak irregular reflection of shock waves in steady flow

The viscosity effects on weak shock wave reflection are investigated with the Navier–Stokes and DSMC flow solvers. It is shown that the viscosity plays a crucial role in the vicinity of three-shock intersection. Instead of a singular triple point, in viscous flow there is a smooth three shock transition zone, where one-dimensional shock jump relations cannot be applied. At the flow parameters corresponding to the von Neumann reflection, when no inviscid three-shock solution exists, the computations predict an irregular shock-wave configuration similar to that observed previously in experiments. The existence of a viscous zone in the region of shock-wave interaction allows a continuous transition from the parameters behind the Mach stem to the parameters behind the reflected shock, which is impossible in the inviscid three-shock theory. Results of numerical simulations agree qualitatively with the conclusions of the approximate viscous theory, which describes the flow in the vicinity of the three-shock intersection.     

To development of air heat pumps for operating in Russian climate

The air heat pump (HP) driven from GTP, created on the basis of aircraft GTE removed from service, is considered. The heat pump uses ambient air from negative (?40 °C) to positive (+15 °C) temperature values as a low-grade heat source and provides heating temperature in a range from 100 to 250 °C with the performance factor 2.5–3.2. The high technological burning of gas decreases its consumption for heating on the average by a factor of 1.5 in comparison with an ordinary boiler-house. Cold HP exhaust within the range of ? 50 … ? 80 °C is fed both to a drive GTP and an integrated electric energy generating GTP, this increasing their specific power by a factor of 1.2–1.4 and efficiency up to a factor of 1.05–1.1. In standard HPs designed for operation with low-grade heat sources from +5 to +10°C, the heating temperature does not exceed +60 … +65 °C for the performance factors indicated.     

The main results of EVA medical support on the Mir Space Station

The aim of this paper is to review the main results of medical support of 78 two-person extravehicular activities (EVAs) which have been conducted in the Mir Space Program. Thirty-six male crewmembers participated in these EVAs. Maximum length of a space walk was equal to 7 h 14 min. The total duration of all space walks reached 717.1 man-hours. The maximum frequency of EVA's execution was 10 per year. Most of the EVAs (67) have been performed at mission elapsed time ranging from 31 to 180 days. The oxygen atmosphere of the Orlan space suit with a pressure of 40 kPa in combination with the normobaric cabin environment and a short (30 min) oxygen prebreathe protocol have minimized the risk of decompression sickness (DCS). There has been no incidence of DCS during performed EVAs. At the peak activity, metabolic rates and heart rates increased up to 9.9-13 kcal/min and 150-174 min-1, respectively. The medical problems have centred on feeling of moderate overcooling during a rest period in a shadow after the high physical loads, episodes with tachycardia accompanied by cardiac rhythm disorders at the moments of emotional stress, pains in the muscles and general fatigue after the end of a hard EVA. All of the EVAs have been completed safely.