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Record 1 of 56091
Sensor for Direct Measurement of the Boundary Shear Stress in Fluid Flow
External Online Source: hdl:2014/41997
Author and Affiliation:
Bao, Xiaoqi(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Badescu, Mircea(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Bar-Cohen, Yoseph(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Lih, Shyh-Shiuh(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Sherrit, Stewart(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Chang, Zensheu(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Chen, Beck(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Widholm, Scott(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Ostlund, Patrick(Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States)
Abstract: The formation of scour patterns at bridge piers is driven by the forces at the boundary of the water flow. In most experimental scour studies, indirect processes have been applied to estimate the shear and normal stress using measured velocity profiles. The estimations are based on theoretical models and associated assumptions. However, the turbulence flow fields and boundary layer in the pier-scour region are very complex. In addition, available turbulence models cannot account accurately for the bed roughness effect. Direct measurement of the boundary shear and normal stress and their fluctuations are attractive alternatives. However, this approach is a challenging one especially for high spatial resolution and high fidelity measurements. The authors designed and fabricated a prototype miniature shear stress sensor including an EDM machined floating plate and a high-resolution laser optical encoder. Tests were performed both in air as well as operation in water with controlled flow. The sensor sensitivity, stability and signal-to-noise level were measured and evaluated. The detailed test results and a discussion of future work will be presented in this paper.
Publication Date: Mar 07, 2011
Document ID:
20120004229
(Acquired Apr 18, 2012)
Subject Category: FLUID MECHANICS AND THERMODYNAMICS
Document Type: Conference Paper
Meeting Information: 18th Annual International Symposium on Smart Structures/NDE; 7-10 Mar. 2011; San Diego, CA; United States
Financial Sponsor: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA, United States
Federal Highway Administration; Washington, DC, United States
Organization Source: Jet Propulsion Lab., California Inst. of Tech.; Pasadena, CA, United States
Description: 8p; In English; Original contains color illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: FLUID FLOW; BOUNDARY LAYER FLOW; SHEAR STRESS; FLOW DISTRIBUTION; TURBULENCE MODELS; WATER FLOW; SURFACE ROUGHNESS; SIGNAL TO NOISE RATIOS; VELOCITY DISTRIBUTION; FABRICATION; STABILITY
Other Descriptors: SENSORS; SHEER STRESS; FLUID FLOW
Availability Source: Other Sources
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Last Modified: April 18, 2012
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