Experimental Study of Flow Oscillation in a Rectangular Jet-Driven Tube

1990 ◽  
Vol 112 (1) ◽  
pp. 23-27 ◽  
Author(s):  
J. Iwamoto
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Steady Flow ◽  
Oscillatory Flow ◽  
Necessary Conditions ◽  
Experimental Results ◽  
Flow Oscillation ◽  
Rectangular Jet ◽  
Rectangular Tube

Several papers, mainly of a theoretical nature, have been published on the oscillatory flow in a Hartmann-Sprenger tube. Quantitative exploration of the flow field has proved difficult and details are lacking. In the present work, using a rectangular tube, synchronous shadow-photography has been applied to visualize the flow field during stable oscillatory flow. The measurement of pressure has also been made for the case of steady flow when both ends of the tube are open. From these experimental results the necessary conditions for starting and maintaining a stable oscillatory flow in an H-S tube have been established.

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

An experimental study of suddenly expanded rectangular jet flow field

1991 ◽  
Vol 18 (1) ◽  
pp. 1-9
Author(s):  
E. Rathakrishnan ◽  
T.J. Ignatius ◽  
Channa Raju
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Jet Flow ◽  
Rectangular Jet

Numerical predictions of ship motions at high forward speed

1991 ◽  
Vol 334 (1634) ◽  
pp. 241-252 ◽  
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Steady Flow ◽  
Added Mass ◽  
Numerical Results ◽  
Experimental Results ◽  
Ship Motions ◽  
Forward Speed ◽  
Numerical Predictions

A theory for ship motions at high forward speed is presented. The theory includes interaction between the steady and unsteady flow field. Numerical results for the steady flow and added mass and damping are compared with experimental results.

Modeling and Experimental Study of Flow Forces for Unstable Valve Design

2003 ◽  
Author(s):  
Qinghui Yuan ◽  
Perry Y. Li
Keyword(s):  
Experimental Study ◽  
Flow Control ◽  
Steady Flow ◽  
Flow Rate ◽  
High Flow ◽  
High Flow Rate ◽  
Experimental Results ◽  
Valve Design ◽  
Electromagnetic Actuators ◽  
New Models

Single stage electrohydraulic flow control valves are currently not suitable in high flow rate and high frequency applicaitons. This is due to the very significant flow induced forces and the power/force limitation of electromagnetic actuators that directly stokes the spool. An unstable valve has been proposed that can utilize the flow forces to achieve fast responses at high flow rate. In this paper, we model the flow forces, including both steady and transient, of a directional flow control valve for incompressible and viscous fluid. In particular, the viscosity effect and non-orifice flux are investigated. The new models have been verified by CFD analysis to be more accurate than the old models. The paper also presents a systematic experimental study on the flow forces, in particular on the steady flow forces. The estimates according to our new models, revised slightly due to the limitation of the experiment, are consistent with the experimental results. Both the experimental results and the modeling estimation show that, for an unstable valve with negative damping length, both transient and steady flow forces can help to achieve the higher spool agility. The satisfactory modeling and experimental study on the flow forces give us a grounding for the future research of unstable valve design.

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

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