Fluctuations of the flow parameters of an incompressible viscous fluid in a collar-type flow throttling device

The flow in channels of the labyrinth seal type with one or two throttling stages is calculated on the interval of Reynolds numbers Re from 1.9·10⁴ to 4.5·10⁵. The nonsteady flow structure and the distribution and fluctuations of the pressure on the body of the labyrinth are investigated. The results are compared with the data of a physical experiment.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 3–8, January–February, 1990.     

Frictional instability of a train of elastically connected bodies

Leningrad State Steelworks Research and Design Institute. Leningrad Mining Institute. Translated from Prikladnaya Mekhanika, Vol. 25, No. 7, pp. 110–115, July, 1989.     

Assessment of a quintuple hotwire measurement technique for highly turbulent flows

A five-wire calibration and measurement technique is presented, which is an extension of the four-wire method developed by Döbbeling et al. (1990a, b). From numerical simulations of the uniqueness domain and the angular resolution it is concluded that the uniqueness domain of the quintuple technique can be expanded to a hemisphere as opposed to the four-wire techniques which are restricted to a conical domain of about 40° half angle. Measurements of the mean velocities and Reynolds stresses in a low-turbulence jet and in grid turbulence confirm and complement the results of the numerical simulations. It is thus shown that the quintuple method achieves increased accuracy in an expanded measurement range.The work of D. Hölzer, student of engineering at the University of Karlsruhe, and the support of W. Paulat and W. Pfeffinger in writing the data aquisition software, and H. Klette who manufactured the probe, is gratefully acknowledged. This work was supported by the Deutsche Forschungsgemeinschaft within the framework of the Sonderforschungsbereich 167, Hochbelastete Brennräume- Stationäre Gleichdruckverbrennung, Teilprojekt A10.     

Measurement of the thickness of a fluid layer by light absorption

A method to measure the thickness of a fluid layer and thus the depth of the interface between two layers has been developed. It uses light absorption by dye and quantitative analysis of video images. Its main advantages are that it is not intrusive and that the places and times for which measurements are made can be chosen after the experiment and so be optimally related to particular phenomena.     

Accuracy of thermocouples in radiant-heat testing

Results of an investigation of the accuracy of iron-constantan thermocouples in measuring transient surface temperatures produced by radiant heating on metallic specimens are given. The criterion of thermocouple accuracy was derived from the theory of heat conduction. The thermocouples were tested on metallic specimens of different thicknesses at varying heating rates. Comparison of these results with analytical criteria permitted quantitative determination of thermocouple errors.     

An LDV system for turbulence length scale measurements

An LDV system for making spatial correlation measurements of velocity fluctuations in turbulent nonreacting and reacting flows is presented. The LDV system is the dual beam type and consists of an elongated probe volume and a two-point optical fiber detector. Results are presented of the integral length scale measured in a nonreacting grid generated turbulent flow.A version of this paper was presented at the ASME Winter Annual Meeting of 1984 and printed in AMD, Vol. 66     

Effect of nonconducting side walls on induced end electric currents

The effect of conditions governing the closing of induced electric currents on the total electrical and dynamical characteristics of the motion of a plasmoid through the rectangular channel of an electric-discharge tube in a nonuniform transverse magnetic field was investigated. It was shown that the electric current can be cut to half by introducing a fairly long and thin nonconducting side wall into the channel in the zone of end currents. The length of the inserted side wall must be not less than 6 channels in order to keep the axial electric current from flowing around the side wall.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 116–121, November–December, 1970.The author is indebted to A. B. Vatazhin for kind assistance rendered in the work and for helpful discussions of the article.     

Some new techniques for scattered-light photoelasticity

This paper describes some new techniques for determining the directions of the secondary principal stresses and their difference in scattered-light photoelasticity. These new techniques do not employ the compensator and are capable of obtaining the same degree of accuracy as the compensator method.