On the statistical characteristics of a flow noise field inside a flexible liquid‐filled cylindrical array

1998 ◽  
Vol 104 (3) ◽  
pp. 1813-1813
Author(s):  
Boris Aronov ◽  
David A. Brown
Author(s):  
S Li ◽  
Y Zhang ◽  
F G Hammitt

Pressure pulses emitted from cavitating venturi flows are measured and investigated statistically. The results show that according to the degree of cavitation, the overall pressure pulsations consist of different combinations of three components, that is basic flow noise, cavitation pulses and low-frequency pressure fluctuations, due primarily to overall loop characteristics. The statistical characteristics are presented and compared. It is believed that the low-frequency fluctuations result from a resonant interaction between the cavitation ‘cloud’ and the liquid portion of the closed loop. They occur near cavitation inception, reach a maximum at a particular cavitation number, σres, then gradually disappear for increased σ. Their frequency is basically constant for all σ. An empirical-theoretical model of this behaviour is presented.


2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2003 ◽  
Vol 59 (3-4) ◽  
pp. 10
Author(s):  
Ye. V. Tarnavsky ◽  
G. P. Kulemin

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