Characterisation of non-linear viscoelastic foods by the indentation technique

A method to determine the non-linear viscoelastic constitutive constants from indentation force–displacement data corresponding to different indentation speeds has been developed. The method consists of two parts. In the first part, the force–displacement data is expressed as two functions which represent the strain and the time-dependent responses, respectively. From these functions, the time-dependent constants and the instantaneous force–displacement response are obtained. In the second part, the strain-dependent variables are determined from the instantaneous force–displacement response through an inverse analysis based on the Levenberg–Marquardt method. The method was verified by numerical experiments using the properties of cheese as examples.     

On equilibrium stability of an elastic-viscoplastic medium

We consider the stability of an elastic-plastic medium when one part of the body is in an elastic state and the other part in a plastic state.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 86–92, September–October, 1970.     

Suppression of auto-oscillations in wind tunnels with open working part

The results are given of an experimental investigation of the acoustic method of auto-oscillation suppression in wind tunnels of closed type with open working part.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 126–132, January–February, 1982.     

Interaction between the boundary layer and a supersonic flow when part of the wall is rapidly heated

There have been many theoretical studies of aspects of the unsteady interaction of an exterior inviscid flow with a boundary layer [1–9]. The mathematical flow models obtained in these studies by the method of matched asymptotic expansions describe a wide range of phenomena observed experimentally. These include boundary layer separation near the hinge of a flap, the flow in the neighborhood of the trailing edge of an oscillating airfoil [1–2], and the development and propagation of perturbations in a boundary layer excited by an oscillating wall or some other way [3–5]. The present paper studies the interaction of an unsteady boundary layer with a supersonic flow when a small part of the surface of a body in the flow is rapidly heated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 66–70, January–February, 1984.     

Law of heat transfer in the region of a gas curtain

The article gives the result of an experimental investigation of heat transfer in the region of a gas curtain behind the permeable part of the surface in a subsonic turbulent boundary layer in the range of blowing intensities j=0.001–0.04.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 160–163, March–April, 1976.The authors thank G. A. Lyubimov for his continuing interest and aid in the work.     

Investigation of unsteady flow structure during discharge of a shock-heated gas

This paper examines the structure of the near-gasdynamic section of a jet discharging into a rarefied volume. The experimental part of the article deals with unsteady discharge of a high-temperature gas. Discharge from a slot and from a circular aperture is investigated for air, nitrogen, CO₂, and argon with nonuniformities from 20–200. Approximate relations are obtained to describe the motion of the front of a discharging substance in dimensionless coordinates and the associated perturbation along the flow axis. It is established that the time for a steady geometric structure to form in the gasdynamic section of the jet is greater than the values obtained from data available in the literature.Translated from Zhurnal Prikladnoi Mekhaniki i Teoreticheskoi Fiziki, No. 5, pp. 34–40, September–October, 1973.     

Erratum to “Bistable Waves in an Epidemic Model” [<Emphasis Type="Italic">J. Dynam. Diff. Eq.</Emphasis> 16, 679--707 (2004)]

The existence, uniqueness up to translation and global exponential stability with phase shift of bistable travelling waves are established for a quasi- monotone reaction–diffusion system modelling man–environment–man epidemics. The methods involve phase space investigation, monotone semiflows approach and spectrum analysis.Dedicated to Professor Shui-Nee Chow on the occasion of his 60th birthday; Supported in part by the NSERC of Canada.     

Tension–compression asymmetry of phosphor bronze for electronic parts and its effect on bending behavior

In-plane tension and compression experiments on copper alloy sheets (phosphor bronze) and 6000 series aluminum alloy sheets (AA6016-T4) were conducted using a specially designed testing apparatus. The apparatus is equipped with comb-type dies so that stress–strain curves of a sheet specimen subjected to tension followed by compression, and vice versa, can be measured without buckling of the specimen, as well as those for monotonic tension and compression. A difference was observed in the flow stresses between tension and compression for the as-received copper alloy, but not for the aluminum alloy. Moreover, stress reversal tests, such as tension followed by compression and compression followed by tension, were carried out in order to measure the Bauschinger effect. In the second part of the experiment, bending moment–curvature diagrams were measured for the as-received and pre-stretched specimens. The bending moment–curvature diagrams were compared with those calculated using the stress–strain curves obtained from the tension–compression tests, and were in good agreement with those calculated with the tension–compression asymmetry and the Bauschinger effect correctly reproduced.     

Experimental study of heat and mass transfer from a horizontal cylinder in downward air-water mist flow with blockage effect

An experimental study was made on convective heat and mass transfer from a horizontal heated cylinder in a downward flow of air-water mist at a blockage ratio of 0.4. The measured local heat transfer coefficients agree fairly well with the authors' numerical solutions obtained previously for the front surface of a cylinder over the ranges mass flow ratio 0–4.5×10⁻², a temperature difference between the cylinder and air 10–43 K, gas Reynolds number (7.9–23)×10³, Rosin-Rammler size parameter 105–168 μm, and dispersion parameter 3.4–3.7. Heat transfer augmentation, two-pahse to single-phase of greater than 19 was attained at the forward stagnation point. For heat transfer in the rear part of the cylinder, an empirical formula is derived by taking into account the dimensionless governing variables, that is, coolant-feed and evaporation parameters.     

Experimental investigation in filtration of hydrocarbons with mass transfer

The results are given of an experimental investigation into the process of extraction from a porous medium of a liquid hydrocarbon (precipitated condensate) filling part of the pore space by means of hydrocarbon solvents.Translated from Izyestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 167–170, September–October, 1979.     

On the possibility of enhancing the efficiency of tangential blowing of a slit jet from an airfoil surface

Experimental results are presented for a teardrop-shaped wing section with tangential slit jet blowing in the forward part of the section. It is shown that such airfoils can provide a lift significantly greater than the lift which can be achieved by blowing a tangential slit jet from a wing of ordinary shape with a flap.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 182–186, July–August, 1996.     

Calculation of a supersonic gas jet exhausting into vacuum from a nozzle with an inclined exit

A study is made of the problem of supersonic exhausting of ideal gas into vacuum from a conical nozzle with inclined exit. The solution is sought in a region including part of the flow where the projection of the velocity vector of the gas onto the nozzle axis can be less than the local velocity of sound and take negative values.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 185–186, May–June, 1982.     

Bistable Waves in an Epidemic Model

The existence, uniqueness up to translation and global exponential stability with phase shift of bistable travelling waves are established for a quasimonotone reaction–diffusion system modelling man–environment–man epidemics. The methods involve phase space investigation, monotone semiflows approach and spectrum analysis.Dedicated to Professor Shui-Nee Chow on the occasion of his 60th birthday.Supported in part by the NSERC of Canada     

Large-Scale Streamwise Vortices in the Supersonic Part of a Permeable Nozzle

Large-scale streamwise vortices in the vicinity of a perforated wall in the supersonic part of the nozzle are studied. The governing effect of gas inflow through a perforated wall on origination and parameters of streamwise vortices is experimentally established.__________Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 5, pp. 68–75, September–October, 2005.     

ORSIS – News and further developments

The paper deals with the simulation program Off Road Systems Interactive Simulation (ORSIS) which is the w,orldwide leading simulation tool for off road driving of wheeled vehicles. Even though the present state of development allows a very realistic simulation of the man–vehicle–terrain system, there is continuous further improvement in the computer program’s detail. Some of the recent innovations integrated into the program are presented in this paper. These examples were chosen in a way that the scope of the further developments can be demonstrated. They represent three main directions of the work carried out: the refining of the tire–soil-model, the integration of new technologies and subsystems into the vehicle model and the improvement of the man–machine–interface especially in driving simulators.The first part of the paper describes a further development of the tire–soil-model. A significant improvement has been achieved to include the influence of slippery surfaces on traction in combination with the tire tread pattern. Results from finite element method (FEM) as well as real measurements were used to build up an approach, which qualitatively allows the influence of the positive–negative portion of the tire tread and the lug height of the tire tread on traction to be considered. The basic idea is very simple and straightforward. Moreover the calculation costs are very low, so the enhancement does not affect real time operation.In the second part a physical model for the central tire inflation system (CTIS) is presented. With this model it is possible to simulate the complete pneumatic system of a CTIS, including the air compressor with an accumulator, the pressure line and the wheel valves. The components are modelled by their physical parameters, so an adaptation to different existing tire-pressure-control-systems (TPC) can be made. The paper presents a short review of the modelling and a first validation using real measurements. Furthermore the influence of each parameter, e.g. the discharge flow of the compressor on the inflation time, is presented.The third part of the paper describes a further development of the visualization system. The ORSIS OpenGL graphic engine was separated from the main ORSIS simulation and can be run on different PCs controlled via a network. It is therefore possible to build up very cheap multi-channel visualization systems using consumer PCs running under LinuX. The fact that ORSIS itself is running on a normal PC allows the assembly of comparatively cheap driving simulators of a high end simulation quality.     

Design of a wing airfoil in a flow with a separated turbulent boundary layer

The problem of designing the contour of an airfoil in a viscous (incompressible and compressible) flow with a separated turbulent boundary layer from a pressure distribution given on the separationless part of the contour is solved using the boundary layer theory together with the separated flow model proposed in [1]. Numerical calculations are carried out to demonstrate the possibilities of the method.Kazan'. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.3, pp. 83–91, May–June, 1994.     

Natural convection in a porous bed with a permeable boundary

Natural convection in a vertical porous bed heated from the side was investigated numerically for the case where mass transfer occurs between the bed and the surroundings. On the permeable part of the boundary we assign conditions of the first or second kind for the pressure, which corresponds to a free surface or a thin permeable skin. We obtained information about the structure and regimes of steady convection in the bed and the dependences of the mean and local heat-transfer characteristics on the Rayleigh number. The results are compared with the results of [1–3].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 145–148, July–August, 1978.The author thanks V. I. Polezhaev for supervision of the work.     

Some families of exact solutions of the equations of two-dimensional shallow water theory

Results are presented of a study of the exact solutions of the equations of two-dimensional unsteady and steady shallow water theory, based on the group properties of these equations. The first part presents the group properties of the equations in question; the second part presents the invariant solutions of these equations.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 10, No. 6, pp. 62–71, November–December, 1969.The author wishes to thank L. V. Ovsyannikov and N. Kh. Ibragimov for valuable guidance in carrying out this study.     

Design of airfoil with flap simulated by a point vortex

The method of quasisolutions of inverse boundary-value problems (see [4]) is used to solve the problem of designing an airfoil with a flap, replaced by a fixed vortex, from given velocity distribution along the contour of the wing main part. Profiles are constructed and the effect of the flap (vortex) on the shape and aerodynamic properties of the mechanized wing is examined.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 3–9, January–February, 1992.     

Influence of thermal inhomogeneity of the boundary on the forced motion of a viscous fluid in a plane layer

Numerical solution of the Navier-Stokes equations is used to investigate the laminar motion of an incompressible fluid in a plane layer when part of the lower boundary has a temperature different from the rest of the lower boundary. The problem is solved in the Boussinesq approximation.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 171–173, January–February, 1982.