Kinetic droplet evaporation in a turbulent air jet

Droplet evaporation in a turbulent air jet is considered for conditions such that the evaporation rate is determined by the evaporation kinetics for the individual droplets rather than by the diffusion rate of the air in the jet. Numerical solution of the equations by computer has shown that the mean air speed in the jet has little effect on the droplet evaporation in the range covered. A simplified solution is presented for the dispersal of an evaporating impurity in a jet. Experiments confirm that this solution is correct, and they show that the turbulent pulsations play a large part, with the result that an initially monodisperse system becomes more and more polydisperse away from the jet.     

Dynamics of the cavitation zone during an underwater explosion near a free surface

The problem of the development of the cavitation zone and the rarefaction wave profile in the region of regular reflection of the spherical shock wave of an underwater explosion from a free surface is analyzed for the axisymmetric formulation within the framework of a model of the two-phase medium consisting of a liquid with cavitation nuclei of the free gas uniformly distributed in it. An example of the calculation of the rarefaction wave profile and the zone of visible cavitation at different times is given for the case of the explosion of 1-g charge at depths of 3 and 5.3 cm for an initial volumetric gas concentration of 10^?11 and an initial cavitation nucleus radius of 5 · 10^?5 cm. The results of the calculation are compared with experiment.     

Transfer of energy from an evaporating drop in a vapor medium

The article considers the temperature distribution around an evaporating drop in a vapor medium. The transfer of energy is effected by molecular thermal conductivity, convection, and radiation. The mean length of the free flight path of the radiation considerably exceeds the characteristic distance at which the temperature changes. The times required for relaxation of the temperature to a steady-state value are determined, as well as the characteristic distances at which the temperature distribution changes.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 74–78, January–February, 1972.The authors thank V. G. Levich for his evaluation of the results obtained.     

Development of ship waves in a nonhomogeneous liquid

The article discusses the three-dimensional problem of unsteady-state waves arising on a free surface and at the interface between two liquids of different densities, with motion of the source. Analogous problems for steady-state waves in a two-layer liquid have been investigated in [1–6], and for unsteady-state waves in a homogeneous liquid in [7, 8].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 137–146, July–August, 1970.     

Strength reduction of metals upon hydrogen chemisorption at the tip of a crack

When hydrogen interacts with the freshly formed surface, the interatomic bonds at the tip of a crack in the single crystal of a metal are known to break. The decrease in the brittle strength of the single crystals of metals in the presence of hydrogen in the crack compared with the strength of the same metal in the absence of hydrogen is estimated quantitatively using comparative criteria of brittle strength. Lavrent'ev Institute of Hydrodynamics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 3, pp. 173–178, May–June, 1998.     

Supersonic flow over a cone with heat release in the neighborhood of the apex

Supersonic flow over a cone mounted in the wake of a spherical source of heat release is investigated. The free-stream nonuniformity generated by the source leads to effective drag reduction.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 110–114, March–April, 1993.     

Heat transfer in flow past a continuously moving semi-infinite flat plate in transverse magnetic field with heat flux

Thermal boundary layer on a continuously moving semi-infinite flat plate in the presence of transverse magnetic field with heat flux has been examined. Similarity solutions have been derived and the resulting equations are integrated numerically. This investigation has indicated a fall in the temperature of the thermal boundary layer with increase in magnetic field parameter.

---

Wärmeübertragung in Strömungen an einer gleichmäßig bewegten, halbunendlichen ebenen Platte in einem quergerichteten Magnetfeld mit Wärmefluß

Zusammenfassung Es ist die thermische Grenzschicht auf einer gleichmäßig bewegten, halbunendlichen ebenen Platte in einem quergerichteten Magnetfeld mit Wärmefluß untersucht worden. Ähnlichkeitslösungen sind abgeleitet und die erhaltenen Gleichungen numerisch integriert worden. Diese Untersuchung hat einen Rückgang der Temperatur in der thermischen Grenzschicht mit steigendem Magnetfeldparameter nachgewiesen.

     

Structures and regimes of shear flow in a plane cavity with translating boundaries

Stability of shear flow in a plane cavity whose boundaries translate in opposite directions is analyzed by solving the nonstationary Navier-Stokes equations numerically. It is shown that, depending on the Reynolds number and the cavity aspect ratioH/R, there may exist either a single-vortex, or a multi-eddy, or an intermediate flow regime with a bridge, all of which are stable. No oscillatory regime was found forH/L=0.1–10 and Re=1–3000.Nizhnii Novgorod, Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 53–56, March–April, 1995.