The Effect of Platen Fins on the Flow-Induced Vibrations of an In-Line Tube Array

2001 ◽  
Vol 123 (4) ◽  
pp. 437-441 ◽  
Author(s):  
D. S. Weaver ◽  
S. Ziada ◽  
Z. Sun ◽  
P. Feenstra
Keyword(s):  
Experimental Study ◽  
Vortex Shedding ◽  
Transverse Flow ◽  
Streamwise Direction ◽  
Stability Threshold ◽  
Fluidelastic Instability ◽  
Flow Induced Vibrations ◽  
The Stability

This paper presents the results of an experimental study of the effect of streamwise “platen” fins on the fluidelastic instability of an in-line tube array. The fins are fixed parallel to the axis of the tubes in the streamwise direction and effectively prevent any transverse flow between streamwise tube rows. A geometrically identical, dynamically scaled bundle of finless tubes were used as a datum case for comparison. The results showed that, while the fins eliminate vortex shedding, they enhance the fluidelastic coupling between adjacent tubes and substantially reduce the stability threshold.

An Experimental Study of the Effect of Tube-to-Tube Ties on Fluidelastic Instability in an In-Line Tube Array

1999 ◽  
Vol 122 (1) ◽  
pp. 50-54 ◽  
Author(s):  
David S. Weaver ◽  
Paul Feenstra ◽  
Frank L. Eisinger
Keyword(s):  
Experimental Study ◽  
The Other ◽  
Streamwise Direction ◽  
Stability Threshold ◽  
Other Hand ◽  
Stabilizing Effect ◽  
Fluidelastic Instability ◽  
Pitch Ratio

An experimental study was conducted on the effect of tube-to-tube ties on the fluidelastic instability of an in-line tube array with a streamwise pitch ratio of 1.33 and a transverse pitch ratio of 2.0. Various arrangements of tubes clamped in the streamwise direction were examined. The results showed that clipping two tubes together had a stabilizing effect, but also exhibited substantial hysteresis. On the other hand, longitudinal clipping of three, four, or six tubes together increased the fluidelastic stability threshold by a factor of more than three. [S0094-9930(00)01501-8]

The Effect of Approach Flow Direction on the Flow-Induced Vibrations of a Triangular Tube Array

1983 ◽  
Vol 105 (1) ◽  
pp. 76-81 ◽  
Author(s):  
H. C. Yeung ◽  
D. S. Weaver
Keyword(s):  
Heat Exchangers ◽  
Small Amplitude ◽  
Flow Direction ◽  
Triangular Array ◽  
Incident Flow ◽  
Stability Threshold ◽  
Flow Induced Vibrations ◽  
Pitch Ratio ◽  
Flow Directions ◽  
The Stability

Water tunnel experiments were conducted on an equilateral triangular array of tubes with a pitch ratio of 1.5. Eight tests were run with different array orientations so that the effects of incident flow direction on crossflow induced vibrations could be studied. Small amplitude vorticity response was observed for all orientations except the parallel triangular array. A Strouhal number of 0.57 based on pitch velocity and independent of incident flow directions was found. The fluidelastic threshold for the normal triangular array was found to be about twice that of the parallel triangular array. However, the stability threshold for the normal triangular array was found to be quite sensitive to incident flow direction suggesting that advantage of this higher threshold should not be taken in the design of heat exchangers.

A simulation apparatus for the experimental study of batch reactor control methods

1986 ◽  
Vol 51 (6) ◽  
pp. 1259-1267
Author(s):  
Josef Horák ◽  
Petr Beránek
Keyword(s):  
Experimental Study ◽  
Closed Loop ◽  
Dynamic Properties ◽  
Batch Reactor ◽  
Exothermic Reaction ◽  
Electric Heating ◽  
Batch Reactors ◽  
Exchange Area ◽  
The Stability ◽  
Methods Of Control

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.

Tertiary solutions and their stability in rotating plane Couette flow

1998 ◽  
Vol 358 ◽  
pp. 357-378 ◽  
Author(s):  
M. NAGATA
Keyword(s):  
Reynolds Number ◽  
Couette Flow ◽  
Stability Boundary ◽  
Streamwise Vortex ◽  
Reynolds Numbers ◽  
Time Dependent ◽  
Plane Couette Flow ◽  
Streamwise Direction ◽  
The Stability ◽  
Oscillatory Instabilities

The stability of nonlinear tertiary solutions in rotating plane Couette flow is examined numerically. It is found that the tertiary flows, which bifurcate from two-dimensional streamwise vortex flows, are stable within a certain range of the rotation rate when the Reynolds number is relatively small. The stability boundary is determined by perturbations which are subharmonic in the streamwise direction. As the Reynolds number is increased, the rotation range for the stable tertiary motions is destroyed gradually by oscillatory instabilities. We expect that the tertiary flow is overtaken by time-dependent motions for large Reynolds numbers. The results are compared with the recent experimental observation by Tillmark & Alfredsson (1996).

An experimental study of the stability of mass standards in transit

Metrologia ◽  
2008 ◽  
Vol 45 (2) ◽  
pp. 233-240 ◽  
Author(s):  
K Fen ◽  
E C Morris
Keyword(s):  
Experimental Study ◽  
The Stability ◽  
In Transit
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