6926475981

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Kty Word*: Heat exchangers. Fluidinduced excitation, Periodic excrtation

A computationa! method i* presented for obtaining the steady-state temperatura response* of 1-2 pass heat ex-changers subject to sinusoidal flow ratę changes of large amplituda. The frequency- and amplituda-dapandant da-tcribing functions between the input sinuaoidal flow ratę changes and the fundamental component of the steady-state re*x>n*e of the outlet temperatura of tube-side or shelljide fluid are al» dertved. Numerical examples are given and it is shown that this method can reduce compu-tation time remarkably.

A finite element method is used to determine the yelocity profiles and boundary shear forces for sound propagation in narrow tubes of various sections. The slit, circle. triangle. spuare, rectangle and hexagon sections are considered and the results are shown. From the profiles. the effective density and resi*tivity basad on the mean velocity are given. These can be used to obtain data on attenuatton and abnrption.

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84*1747

OscilUtion Modes in Single-Step Hartmann-Sprenger Tubes

M. Kawahashi, R. Bobone, and E. Brocher Institut de M£canique des Fluides de l'Unlversit£ Aix-Marseille II. 1. rue Honnorat, 13003 Marseille, France, J. Acoust. Soc. Amer., 75. (3). pp 780-784 (Mar 1984) 9 figs, 15 refs

Key Words: Tubes, Fluid-induced excitation, Shock waves, Wave propagation

When a high velocity jet it directad toward the mouth of a tubę c/osed at the downstraem and. targa, nonlinaar Uow otcillations may occur withłn the tuba. Shock waves prope-gate up and down the tubę and generate strong heating of the tubę wali*. The deyice is called a Hartmann-Sprenger tuba (H-S tuba). It ha* been proposed to strengthen the ihock wave* and contaquently the heating effect* by tapering the tubę. Conical and mułtistepped configuration* have been investigated, but also tubes having a suddenarea contraction (single step). This latter geometry Products ramarkabta pressure and thermal heating amplificatlon comparad to a eon sta nt araa tuba. The peper presents theoretical and experimental results obtained for the single-stap H-S tuba.

84*1749

Cakulating Method and Experimental lnvestigation of Dynamie Characteristks of Tubę in Tubę Struć* turę in Tali Buildings

Fan Xiaoqing and Zhang Weiyue J. Bldg. Struć.. 4_(3). pp 1-11 (1983)

CSTA No. 624-83.55

Key Words: Tubes, Concentric structures

A simplified calculation model is proposed for analyzing the dynamie characteristics of tubę in tubę structure. In this model, besides considering bending and shaar deforma-tion, the axial deformation of columnt is taken into account.

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84*1750

Simultaneous, Finite, Gyrosoopic and Rad tal Osctila-tions of Hyperelastic Cylindrical Tubes

A. Ertepinar and T. Tokdemir

Middle East Technical Univ.. Ankara. Turkey, Intl.

J. Engrg. Sci.,.22 (4). pp 375-382 (1984) 5 figs. 7

refs

Key Words: Tubes, Oscillation

Simultanaous. finite, gyroscopic and radial oscillation* of long, crcular cylindrical tubes are investigated. The materiał of the tubę is assumed to be homogeneous, isotropic. hyperelastic and incompressfcle. The theory of finite elas-ticlty is used in the formulation of the problem.

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84*1748

Effectńre Denśties and Renatńrities for Acouatk Propagation in Narrow Tubes

A. Craggsand J.G. Hildebrandt Dept. of Mech. Engrg., Univ. of Alberta. Edmonton, Alberta, Canada, J. Sound Vib.,.22.(3), PP 321-331 (Feb 8,1984) 10 figs. 8 refs

Key Words: Tubes, Sound waves, Wave propagation, Flnite element technigue

84*1751

Flow Induced Bifurcations to Three-Dimensional OaciUatory Motions in Continuous Tubes

A.K. Bajaj and P.R. Sethna

Purdue Univ., West Lafayette, IN 47907, SI AM J. Appl. Math.. (2). pp 270-286 (Apr 1984) 2 figs, 22 refs

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