Experimental Study on Flow Field under a High Speed Shinkansen Train

2012 ◽  
pp. 487-494
Author(s):  
N. Yamazaki ◽  
A. Ido ◽  
T. Kurita ◽  
M. Matsumoto
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed

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.

Experimental Visualization Study on the Explosion Process of Gasoline Vapor in Narrowly-Confined Space

2013 ◽  
Vol 791-793 ◽  
pp. 2108-2111 ◽  
Author(s):  
Jian Jun Liang ◽  
Yang Du ◽  
Yi Hong Ou ◽  
Xin Sheng Jiang ◽  
Hai Bing Qian ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Data Acquisition ◽  
High Speed ◽  
Development Stage ◽  
High Speed Camera ◽  
Confined Space ◽  
Vapor Explosion ◽  
Gasoline Vapor ◽  
Explosion Process

In this paper, experimental study on gasoline vapor explosion was conducted with data acquisition technology of high-speed camera. In the experiments, the flame behaviors and the flow field movements were shot by the high-speed camera, the space pressure were recorded by high-speed dynamic tester, and the explosion process were analyzed refinedly and intuitively. Studies have shown that according to variations of flame behaviors and pressure characteristics, process of gasoline vapor explosion can be divided into four stages: the ignition stage, the development stage, the intensification stage and the plume stage.

An Experimental Study of Influence of Slits in Throat Position on Suppression of Cavitation Instabilities in Liquid Propellant Rocket Inducer

2019 ◽  
Author(s):  
Moena Kanamaru ◽  
Yoshito Kamikura ◽  
Satoshi Kawasaki ◽  
Takashi Shimura ◽  
Iga Yuka
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Pressure Fluctuation ◽  
High Speed ◽  
Cavity Length ◽  
High Speed Camera ◽  
Liquid Propellant ◽  
Suppression Effect ◽  
Suction Performance ◽  
Propellant Rocket

Abstract Experiments of an inducer with symmetric slits were conducted. The purpose of the study is to explore the suppression effect on cavitation instabilities by slits. The slits are located in a throat position in each blade and it means symmetric slits. The experiments are done through measuring pressure fluctuation in the flow field and shaft displacement and visualization using high speed camera. In this study, the head performance, the suction performance, the cavity length and the occurrence range and the strength of the cavitation instabilities are compared with the results of inducer without slit. As a result, the slit in throat position does not give bad effect on head performance, improves suction performance, and has a relation to suppression of oscillation of cavitation instabilities because of the suppression effect of cavity length, although the occurrence range of super-synchronous rotating cavitation unfortunately increases because the cavity develops slowly.

scholarly journals Experimental Study of Impingement Effusion Cooled Double-Wall Combustor Liners: Aerodynamic Analysis with Stereo-PIV

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6191
Author(s):  
Thomas Jackowski ◽  
Maximilian Elfner ◽  
Hans-Jörg Bauer ◽  
Katharina Stichling ◽  
Marco Hahn
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Low Frequency ◽  
Flow Region ◽  
Outer Wall ◽  
System Stability ◽  
Complex Flow ◽  
Hot Gas ◽  
Double Wall

A new experimental study is presented for a combustor with a double-wall cooling design. The inner wall at the hot gas side features effusion cooling with 7-7-7 laidback fan-shaped holes, and the outer wall at the cold side features an impingement hole pattern with circular holes. Data are acquired to asses the thermal and aerodynamic behavior of the setup, using a new, scaled up, engine similar test rig. Similarity includes Reynolds, Nusselt and Biot numbers for hot gas and coolant flow. Different geometrical setups are studied by varying the cavity height between the two walls and the relative alignment of the two hole patterns at two different impingement Reynolds numbers. This article focuses on the aerodynamic performance of the setup. Instationary flow data are acquired, using a high speed stereo PIV setup. For each geometrical configuration, approximately 20 planes are recorded with a data rate of 1000 by traversing the flow region of interest in the cavity between the two specimen. This fine resolution allows the reconstruction of 3D flow fields for the mean data values and an extensive analysis of transient phenomena at each plane. Time averaged data and jet-center plane transient data are presented in detail. The results show a complex flow field with a hexagonal vortex pattern in the cavity, which is mainly influenced by the cavity height and the relative alignment of the two walls. The jet Reynolds number shows small influence when analyzing normalized data. Small cavity heights show a less developed flow field with less stable vortex systems. The alignment shows a similar influence on vortex system stability, with the aligned case performing better. Additionally, statistical analysis of the jet flow and frequency domain analysis of the jet and the effusion flow are presented, showing the damping capability of the cavity, especially at increased cavity heights, and a residual low frequency pulsation of the effusion cooling inflow.

An experimental study on the coupling between adjacent Hartmann whistles

2019 ◽  
Vol 18 (2-3) ◽  
pp. 299-316
Author(s):  
Todd Lowe ◽  
Kevin Silas ◽  
George Boggs ◽  
Wing Ng
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Primary Role ◽  
Frequency Locking ◽  
Physical Mechanisms ◽  
Speed Flow ◽  
Close Proximity ◽  
Coupling Dynamics ◽  
Coupling Mode

An experimental study has been conducted to examine interactions between two Hartmann whistles placed in close proximity. Microphone measurements of acoustic emission from the whistles, in addition to high-speed flow field visualizations, were used to assess the physical mechanisms present. A strong coupling mode has been identified that results in frequency locking between the resonators. Observed for only one set of parameters in the experimental matrix, the frequency-locked coupling requires sufficient spacing between the nozzle exit and resonator cup of each whistle to establish the acoustic-driven feedback loop. The visualization results show this coupling to arise due to acoustic excitation from the adjacent resonator, inducing hydrodynamic perturbations that grow sufficiently to alter the flow field around the perturbed resonator. The study indicates that coupling dynamics can play a primary role in dual-whistle resonance and frequency output.

EXPERIMENTAL STUDY OF INFLUENCE OF ACTIVE METHODS OF FLOW CONTROL ON THE FLOW FIELD PAST A CYLINDER

2009 ◽  
Vol 16 (4) ◽  
pp. 353-366 ◽  
Author(s):  
Milan Matejka ◽  
Petr Pick ◽  
Jiri Nozicka ◽  
Pavel Prochazka
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Flow Control
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