scholarly journals Discussion: “Combined Simultaneous Flow Visualization—Hot-Wire Anemometry for the Study of Turbulent Flows” (Falco, R. E., 1980, ASME J. Fluids Eng., 102, p. 174)

1982 ◽  
Vol 104 (1) ◽  
pp. 126-126
Author(s):  
P. Freymuth
Keyword(s):  
Flow Visualization ◽  
Turbulent Flows ◽  
Hot Wire ◽  
Hot Wire Anemometry

Combined Simultaneous Flow Visualization/Hot-Wire Anemometry for the Study of Turbulent Flows

1980 ◽  
Vol 102 (2) ◽  
pp. 174-182 ◽  
Author(s):  
R. E. Falco
Keyword(s):  
Pressure Gradient ◽  
Flow Visualization ◽  
Turbulent Flows ◽  
Unsteady Flows ◽  
Gradient Flows ◽  
Hot Wire ◽  
Visual Patterns ◽  
Favorable Pressure Gradient ◽  
Hot Wire Anemometry ◽  
Scattering Light

The measurement of coherent motions in turbulent and unsteady flows is discussed. A technique which discriminates these motions based upon the patterns they create by scattering light from a fog of tiny oil drops is described. It is shown that hot-wire anemometry can be used in this oil fog so that hot-wire data can be conditionally sampled to the visual patterns, giving directly interpretable measures of the importance of the selected features. The three-dimensionality of the coherent motions can also be directly accounted for, using mutually orthogonal sheets of light. Results of step flows, and zero and favorable pressure gradient flows are described.

Quantification of Mixing Performance in Parallel Jets

Volume 4 ◽  
2004 ◽  
Author(s):  
Nathan E. Bunderson ◽  
Barton L. Smith
Keyword(s):  
Flow Visualization ◽  
Momentum Flux ◽  
Width Ratio ◽  
Hot Wire ◽  
Ambient Fluid ◽  
Jet Mixing ◽  
Mixing Performance ◽  
Flux Condition ◽  
Two Component ◽  
Hot Wire Anemometry

Experiments of unvented parallel planar jets having variable slot widths and velocities are presented. A flow visualization study shows that, for sufficiently large spacing, the jets “flap” and that this motion is maximized for a matched exit momentum flux condition. The extent of the jet mixing with the ambient fluid is investigated using two-component hot wire anemometry. It is demonstrated that the flapping increases mixing of the jets with the ambient. In addition, it is shown that the mixing increases with distance between the jets and with jet-width ratio.

scholarly journals Assessment of uncertainties in hot-wire anemometry and oil-film interferometry measurements for wall-bounded turbulent flows

2018 ◽  
Vol 72 ◽  
pp. 57-73 ◽  
Author(s):  
Saleh Rezaeiravesh ◽  
Ricardo Vinuesa ◽  
Mattias Liefvendahl ◽  
Philipp Schlatter
Keyword(s):  
Turbulent Flows ◽  
Hot Wire ◽  
Oil Film ◽  
Hot Wire Anemometry

Response Compensation Scheme for Constant-Current Hot-Wire Anemometry Based on Frequency Response Analysis

2011 ◽  
Author(s):  
Kazuhide Kaifuku ◽  
Soe Minn Khine ◽  
Tomoya Houra ◽  
Masato Tagawa
Keyword(s):  
Turbulent Flows ◽  
Constant Temperature ◽  
Response Speed ◽  
Wake Flow ◽  
Constant Current ◽  
Response Analysis ◽  
Compensation Scheme ◽  
Hot Wire ◽  
Velocity Fluctuations ◽  
Hot Wire Anemometry

Hot-wire anemometry (HWA) is used for measuring velocity fluctuations such as turbulent flows. It is generally operated in three modes; constant-temperature (CT), constant-current (CC) and constant-voltage (CV) types. The constant-temperature anemometer (CTA) is the mainstream anemometer, while others are rarely used in measuring normal turbulent flows because of their insufficient response speed. However, since the constant-current anemometer (CCA) can be composed of simple circuits, the HWA can be realized at quite a low cost. In this study, the response characteristics of the CCA are theoretically analyzed, and a compensation scheme is proposed. The scheme is experimentally tested in a turbulent wake flow formed behind a cylinder. As a result, it has been confirmed that the root-mean-square (rms) velocities and the power-spectrum distributions compensated by the present scheme agree well with those measured with CTA. Hence, the CCA provides reliable measurement of turbulent velocity fluctuations.

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