Image processing of hydrogen bubble flow visualization for determination of turbulence statistics and bursting characteristics

1985 ◽  
Vol 3 (6) ◽  
pp. 349-356 ◽  
Author(s):  
L. J. Lu ◽  
C. R. Smith
Keyword(s):  
Image Processing ◽  
Flow Visualization ◽  
Bubble Flow ◽  
Hydrogen Bubble ◽  
Turbulence Statistics

An extended use of the hydrogen bubble flow visualization method

AIAA Journal ◽  
1965 ◽  
Vol 3 (6) ◽  
pp. 1203-1203 ◽  
Author(s):  
WILLIAM O. CRIMINALE ◽  
R. W. NOWELL
Keyword(s):  
Flow Visualization ◽  
Bubble Flow ◽  
Visualization Method ◽  
Hydrogen Bubble

Hydrogen bubble flow visualization at low Reynolds numbers.

AIAA Journal ◽  
1969 ◽  
Vol 7 (8) ◽  
pp. 1635-1637 ◽  
Author(s):  
FREDERICK W. ROOS ◽  
WILLIAM W. WILLMARTH
Keyword(s):  
Flow Visualization ◽  
Reynolds Numbers ◽  
Bubble Flow ◽  
Hydrogen Bubble ◽  
Low Reynolds Numbers ◽  
Low Reynolds

An Evaluation of the Hydrogen Bubble Technique for the Quantitative Determination of Fluid Velocities Within Clear Tubes

1967 ◽  
Vol 89 (4) ◽  
pp. 771-777 ◽  
Author(s):  
W. Davis ◽  
R. W. Fox
Keyword(s):  
Quantitative Determination ◽  
Flow Visualization ◽  
Steady Flow ◽  
Hydrogen Bubble ◽  
Entrance Length ◽  
Fluid Velocities ◽  
Clear Plastic ◽  
Hydrogen Bubble Technique

The hydrogen bubble technique for flow visualization is modified for quantitative determination of velocity of water flowing in clear plastic tubes. Calibration tests are reported showing the accuracy which may be expected of the technique. The technique is verified by application to the determination of the hydrodynamic entrance length in steady flow.

Flow Separation in an Aerofoil Cascade

1967 ◽  
Vol 71 (680) ◽  
pp. 559-565 ◽  
Author(s):  
B. R. Clayton ◽  
B. S. Massey
Keyword(s):  
Reynolds Numbers ◽  
Boundary Layer Separation ◽  
Flow Visualisation ◽  
Bubble Flow ◽  
Hydrogen Bubble ◽  
General Behaviour ◽  
Low Reynolds Numbers ◽  
Separation Results ◽  
Visualisation Technique

SummaryThe pattern of flow at low Reynolds Numbers about an aerofoil in a cascade has been illustrated by the hydrogen-bubble flow-visualisation technique. The method has also been adapted tor the accurate experimental determination of the position of boundary-layer separation. Results of the investigation are presented graphically together with photographs showing the general behaviour of the flow in the wake.

Information and estimation in image processing

1987 ◽  
Vol 45 ◽  
pp. 14-17
Author(s):  
B. Roy Frieden
Keyword(s):  
Image Processing ◽  
Optical System ◽  
Large Amplitude ◽  
Communication Theory ◽  
Image Data ◽  
Direct Approach ◽  
Ill Posed

Despite the skill and determination of electro-optical system designers, the images acquired using their best designs often suffer from blur and noise. The aim of an “image enhancer” such as myself is to improve these poor images, usually by digital means, such that they better resemble the true, “optical object,” input to the system. This problem is notoriously “ill-posed,” i.e. any direct approach at inversion of the image data suffers strongly from the presence of even a small amount of noise in the data. In fact, the fluctuations engendered in neighboring output values tend to be strongly negative-correlated, so that the output spatially oscillates up and down, with large amplitude, about the true object. What can be done about this situation? As we shall see, various concepts taken from statistical communication theory have proven to be of real use in attacking this problem. We offer below a brief summary of these concepts.

The quantitative comparison of experimental and simulated diffraction contrast images

1995 ◽  
Vol 53 ◽  
pp. 102-103
Author(s):  
Stuart McKernan
Keyword(s):  
Image Processing ◽  
Personal Computer ◽  
Close Agreement ◽  
Quantitative Comparison ◽  
Image Simulation ◽  
Computing Power ◽  
Diffraction Contrast ◽  
Simulated Images ◽  
Made In

For many years the concept of quantitative diffraction contrast experiments might have consisted of the determination of dislocation Burgers vectors using a g.b = 0 criterion from several different 2-beam images. Since the advent of the personal computer revolution, the available computing power for performing image-processing and image-simulation calculations is enormous and ubiquitous. Several programs now exist to perform simulations of diffraction contrast images using various approximations. The most common approximations are the use of only 2-beams or a single systematic row to calculate the image contrast, or calculating the image using a column approximation. The increasing amount of literature showing comparisons of experimental and simulated images shows that it is possible to obtain very close agreement between the two images; although the choice of parameters used, and the assumptions made, in performing the calculation must be properly dealt with. The simulation of the images of defects in materials has, in many cases, therefore become a tractable problem.

Sign in / Sign up

Export Citation Format

Share Document