Deceleration and deformation of a liquid drop in a gas stream

An analytic method is developed for calculating the nonstationary motion and spreading of two-dimensional and axisymmetric liquid drops in a gas stream. The method is based on an expansion of the Navier-Stokes equations in a small parameter.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 58–69, March–April, 1981.     

Model of the internal circulation of a liquid drop in a gas stream

An analytical model for calculating the internal flow in a drop is proposed. The model is checked by numerically solving the exact boundary-value problem for the Navier-Stokes equations.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 167–170, November–December, 1989.     

Propagation of a signal in a liquid with a continuous distribution of bubble sizes

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 4, pp. 54–60, July–August, 1992.     

Steady rise of a liquid drop in a viscous liquid

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 1, pp. 78–88, January–February, 1992.     

Slow motions of a liquid drop in a viscous liquid

The problem of the fully established slow translational motion of a round drop (bubble) in a viscous liquid was solved by Adamar and Rybchinskii [1, 2]. The results of experimental measurements are rarely in agreement with the Adamar-Rybchinskii formula. This is connected with braking of the flow due to surface-active impurities, which are usually rather numerous in liquids. Nevertheless, we shall consider the problem of the not fully established motion of a drop in the simplest case, assuming that there are no surface-active substances. The article discusses problems of the vibrations and motions of a spherical drop in a viscous liquid, with arbitrary accelerations. An analysis is made of a formula for the force of resistance of a drop of liquid with a high viscosity, an elastoviscous drop, and a particle with slipping-through.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 32–37, November–December, 1975.     

Phenomena of a liquid drop falling to a liquid surface

Two kinds of phenomenon have been observed when a liquid drop falls to a surface of the same liquid. The first, which can nearly always be observed, involves splash and some degree of penetration and cleavage and the conditions for this occurrence are identified. The experimental observations are compared with previous computational results. The second kind of colliding phenomena can be observed only by chance in an ordinary falling drop experiment and appears to be random. It includes the two phenomena investigated in this paper: the floating drop and the rolling drop.     

Numerical analysis of the drop impact onto a liquid film of non-linear viscoelastic fluids

Meccanica - This paper numerically analyzes the crown formation due to a plane two-dimensional drop impact onto a pre-existing film in a viscoelastic fluid. The finite volume method is applied to...     

ATOMIZATION OF A LIQUID DROP BY PULSATION

ＡＴＯＭＩＺＡＴＩＯＮＯＦＡＬＩＱＵＩＤＤＲＯＰＢＹＰＵＬＳＡＴＩＯＮ￥(林松飘，周哲玮)Ｓ．Ｐ．Ｌｉｎ；（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌａｎｄＡｅｒｏｎａｕｔｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＣｌａｒｋｓｏｎＵｎｉｖｅｒｓｉｔｙ，Ｐｏｔｓｄ...     

Normal oscillations of a rotating liquid drop

The problem of determining the frequencies and profiles of surface waves of a liquid drop rotating under conditions of weightlessness is considered. For an ideal liquid, Ritz's method can be applied to a certain quadratic functional to calculate the oscillation frequencies on a computer. For a low-viscosity liquid, using the boundary-layer method, formulas are obtained for the decay rate and the corrections to the oscillation frequencies. The results of the calculations are presented in the form of graph and a table.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 78–87, July–August, 1979.I should like to thank N. D. Kopachevskii for supervision and assistance in the work.     

Dielectric liquid drop in a harmonic electric field

The problem of the shape of a liquid drop and flows inside and outside the drop in a harmonic electric field is theoretically considered using the small-parameter expansion method. Taking the second-order terms into account makes it possible to consider charge transport over the drop surface.     

Breakup and atomization characteristics of mono-dispersed diesel droplets in a cross-flow air stream

This paper describes the microscopic and macroscopic breakup characteristics, as well as the velocity and size distributions, of mono-dispersed droplets in relation to the breakup regimes. For this experiment, a droplet generator equipped with a piezo stack produced mono-dispersed droplets. The droplet-breakup phenomenon due to the cross-flow was captured in microscopic and macroscopic views by using the following: a spark lamp, a Nd:YAG laser, a long distance microscope and a CCD camera as a function of the Weber number. Along with the analysis of the images, the droplet size and velocity distributions were measured in the near nozzle region by a phase Doppler particle analyzer system at bag, stretching and thinning, and catastrophic breakup regimes. The results of this study showed the size and velocity distributions of disintegrated droplets at the bag, stretching and thinning, and catastrophic breakup regimes. In the bag breakup regime, the droplets separated into small and large droplets during breakup. Alternatively, the droplets disintegrated at a shorter duration and formed a cloud, similar to a fuel spray injected through an injector, in the stretching and thinning and catastrophic breakup regimes.     

Variation of drag coefficients in an interacting drop stream

Variation of the drag coefficient of closely spaced drops in a stream injected into a turbulent flow is studied experimentally. Three different regions are identified. In the first region, close to the injector, drops flow in the wake of each other. The drag coefficient in this region is much smaller (by a factor of 4 to 5) than the standard drag coefficient, and its magnitude is dependent on the drop initial spacing. Shortly downstream of the injection point, the transition region starts, where the drag coefficient increases rapidly approaching the drag coefficient of a single isolated drop. And further down-stream when drops are dispersed significantly, the drag coefficient will behave the same way as a single isolated drop.     

Bubble migration inside a liquid drop in a space laboratory

Commercial production of glasses for advanced applications often requires processing techniques substantially different from those in common use. In particular, containerless processing is desirable where melt temperatures are sufficiently high that the container wall reacts chemically with the melt and/or promotes crystallization. An ideal environment for containerless processing is provided by the NASA Space Shuttle program because in orbit, near free fall conditions prevail and little levitation is necessary. In such an environment, however, there are serious problems associated with convective mixing and buoyant fining (bubble removal) of glass melts. Alternate techniques for the promotion of mixing and for managing bubbles in space have been proposed by Subramanian and Cole and include thermocapillarity, rotation, oscillation, etc. This paper will describe these experiments and discuss two of a number of ongoing ground-based projects in support of the flight experiments.