Measurement of contact area, contact pressure and compaction under tires in soft soil

This paper reports about measurements of the contact area of agricultuural tires in a soil bin. Four tires of the dimensions 12.5/80-18, 13.6–28, 16.9–34 and 16.9–26 were tested on a soft sandy loam. Because the existing models for predicting the footprint are complicated, a simplified model has been established, yielding good results. Measured different contact areas of all four tires are nearly constant related to wheel load except for a small increase at higher loads. Using rated loads and applying the appropriate inflation pressure, the ground pressure of a group of similar tires in loose sandy loam is independent of the tire dimensions. Measured soil compaction under at tire a various wheel loads is compared with results obtained by a mathematical model.     

Modelling power requirement for traction tyres with zero sinkage

A model was developed by dimensional analysis to predict the gross traction at zero net traction for traction tyres (11.2–28, 12.4–28, 13.6–28) on a hard surface. Different parameters that affect the torque requirement, namely tyre size, tyre deflection, axle load, and rolling radius, were considered for the analysis. Experiments were conducted to study the effect of various wheel and system parameters on torque and energy consumed per unit distance travelled. The model developed predicts the torque requirement in an acceptable range and can be used as a reference for further traction studies of these tyres in various soils.     

Measurement of the total scattering cross sections of inert gases in the relative energy range 7–17 eV

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 28–32, July–August, 1988.     

Instability of a liquid surface with laser heating

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 28–34, May–June, 1991.     

A class of steady axisymmetric incompressible flows

Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 28–34, November–December, 1990.     

Acoustic Cerenkov radiation and its utilization in holography methods to study moving media

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 30, No. 6, pp. 28–34, November–December, 1989.     

A mixed aerosol-particle charge. The asymptote and interpolation formulas for the electrification current

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 30, No. 6, pp. 23–28, November–December, 1989.     

Self-lubricated transport of aqueous foams in horizontal conduits

The flow characteristics of aqueous foams were studied in a thin flow channel and a round pipe instrumented for pressure gradient and flow rate measurements. The quality of the foam was varied by controlling the volumetric flow rate of liquid and gas, and different flow types were identified and charted. Uniform foams move as a rigid body lubricated by water generated by breaking foam at the wall. A lubrication model leading to a formula for the thickness of the lubricating layer is presented. The formula predicts a layer thickness of 6–8 μm in the channel and 10–12 μm in the pipe. The thickness depends weakly on foam quality. An overall correlation for the friction factor as a function of Reynolds number which applies to both channel and pipe is derived. This correlation is consistent with a model in which a rigid core of foam is lubricated by laminar flow of a water layer in the range of measured thickness.     

Shear-free turbulent diffusion—classical and new scaling laws

We consider the problem of turbulence generation at a vibrating grid in the x₂–x₃ plane. Turbulence diffuses in the x₁-direction. Analyzing the multi-point correlation equation using Lie-group analysis, we find three different invariant solutions (scaling laws): classical diffusion-like solution (heat equation like), decelerating diffusion-wave solution and finite domain diffusion due to rotation. All solutions have been obtained using Lie-group (symmetry) methods. It is shown that if only one spatial dimension is considered, models based on Reynolds averaging are only capable to model either the diffusion-like solution or the decelerating diffusion-wave solution. The latter solution is only admitted under certain algebraic constraints on the model constants; e.g. in case of the K– model the model constants need to obey the relation c₂σ/σ_K=2. Turbulent diffusion on a finite domain induced by rotation is not admitted by any of the classical models. Finally, in the appendix it is shown that Lele's transformation (Phys. Fluids 28(1) (1985) 64) leads to a complete analytic solution of the steady diffusion problem modelled by the K– equation.     

Experimental study on the condensation of supersonic steam jet submerged in quiescent subcooled water: Steam plume shape and heat transfer

The condensation of supersonic steam jet submerged in the quiescent subcooled water was investigated experimentally. The results indicated that the shape of steam plume was controlled by the steam exit pressure and water temperature. Six different shapes of steam plume were observed under the present test conditions. Their distribution as a function of the steam exit pressures and water temperatures was given. As the steam mass velocity and water temperature increase, the measured maximum expansion ratio and dimensionless penetration length of steam plume were in the ranges of 1.08–1.95 and 3.05–13.15, respectively. The average heat transfer coefficient of supersonic steam jet condensation was found to be in the range of 0.63–3.44 MW/m²K. An analytical model of steam plume was found and the correlations to predict the maximum expansion ratio, dimensionless penetration length and average heat transfer coefficient were also investigated.     

Application of the method of integral equations for solving problems of the three-dimensional theory of stability of deformable bodies

Moscow Branch. Translated from Prikladnaya Mekhanika, Vol. 25, No. 12, pp. 28–35, December, 1989.     

Intrusion of die with a near-circular base in a transversally isotropic halfspace

Kiev Institute of Civil-Aviation Engineers. Translated from Prikladnaya Mekhanika, Vol. 26, No. 7, pp. 28–34, July, 1990.     

Two-phase flow measurements with sharp-edged orifices

This paper contains the results of a set of two-phase flow measurements of 4 different ratios of vapor to liquid density (up to 0.328) across a sharp-edged circular orifice. Test fluid was R-113. Tests were carried out upon 3 orifices whose diameter ratios were 0.312, 0.439 and 0.625. The test quality ranged from 0–100%, while the mass velocity from 917–1477 kg/m².s. On the basis of a modified separated flow model, a relationship is developed for the flow rate and quality and is compared with experimental data and 5 proposed correlations. Comparison shows this method can be used to calculate the flow rate or the quality of vapor liquid (or steam water) mixture in the range 0.00455 to 0.328 of the density ratio, and in pipe size ranging from 8 to 75 mm (β = 0.25–0.75).

The RMS error of this method is about 12% when the quality, x, ranges from 2% to 100%.     

Experimental and numerical study of flat momentumless wake

Flat momentumless wake behind wing profile has been studied both experimentally and with numerical simulation based on the second order Reynolds stress turbulence model. Some obtained regular trends of momentumless wake decay are mainly consistent with previous experiments by Dmitrenko et al. (Dmitrenko, Yu.M., Kovalev, I.I., Luchko, N.N., Cherepanov, P.Ya., 1987. J. Eng. Phys. 52, 743–751 (in Russian)), Cimbala and Park (Cimbala, J.M., Park, W.J., 1990. J. Fluid Mech. 213, 479–509; Park, W.J., Cimbala, J.M., 1991. J. Fluid Mech. 224, 29–47). Transverse distributions of statistical characteristics and its evolution along the flow axis depend on initial conditions and body shape. It was shown that characteristic turbulence parameters associated with the wake's width, mean velocity deficit, turbulence kinetic energy, and its dissipation rate are not constant as some of the theories predict.     

Determining the stress state of shells of revolution with complex boundary conditions

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 2, pp. 28–34, February, 1989.     

Coupled deformation,filtration, and heat conduction in media with quasi-spheroidal pores

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 12, pp. 19–28, December, 1989.     

Nonaxisymmetric waves in an orthotropic timoshenko shell containing a viscous fluid

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 26, No. 12, pp. 22–28, December, 1990.     

Effective thermoelastic constants of discretely-fibrous composites with anisotropic components

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 24, No. 10, pp. 21–28, October, 1988.     

Effect of tube diameter on Preston tube calibration curves for the measurement of wall shear stress

The effect of tube diameter (d) on Preston tube calibration curves for the measurement of wall shear stress (τ_w) in a zero pressure gradient turbulent boundary layer has been investigated. Five different outside diameter tubes of 1.46, 1.82, 3.23, 4.76 and 5.54 mm, corresponding to (d/δ) of 0.022, 0.027, 0.048, 0.071 and 0.082 were used to measure τ_w at Reynolds numbers based on momentum thickness (R_θ) of 2800–4100. The calibration curves of Patel (V.C. Patel, J. Fluid Mech. 23 (part I) (1965) 185–208) and Bechert (D.W. Bechert, AIAA J. 34 (1) (1995) 205–206) are both dependent on the tube diameter. The maximum difference in the τ_w measurements from the different tubes using Patel's calibration is about 8%, while Bechert's calibration gives a maximum difference of approximately 18%.