Two- and Three-Dimensional Analyses of Surfaces According to the E-System

1974 ◽  
Vol 188 (1) ◽  
pp. 691-699 ◽  
Author(s):  
M. S. Shunmugam ◽  
V. Radhakrishnan
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Roughness Measurement ◽  
Doubly Curved ◽  
Dimensional Assessment

The E-system of roughness measurement can be used either for a two-dimensional or a three-dimensional assessment of surface roughness. The procedure for computing the two- and three-dimensional envelopes from digitized profiles is briefly explained. This method will be useful for verifying the results obtained by practical instruments. The filtering characteristic of the E-system, when used for two- and three-dimensional roughness measurement, is analysed with reference to theoretical profiles. Various skid configurations are studied using a doubly curved skid simulated by a computer.

Acoustic receptivity and evolution of two-dimensional and oblique disturbances in a Blasius boundary layer

2001 ◽  
Vol 432 ◽  
pp. 69-90 ◽  
Author(s):  
RUDOLPH A. KING ◽  
KENNETH S. BREUER
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Acoustic Wave ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Surface Waviness ◽  
S Wave ◽  
Boundary Layer Instability ◽  
Blasius Boundary Layer ◽  
Tollmien Schlichting

An experimental investigation was conducted to examine acoustic receptivity and subsequent boundary-layer instability evolution for a Blasius boundary layer formed on a flat plate in the presence of two-dimensional and oblique (three-dimensional) surface waviness. The effect of the non-localized surface roughness geometry and acoustic wave amplitude on the receptivity process was explored. The surface roughness had a well-defined wavenumber spectrum with fundamental wavenumber kw. A planar downstream-travelling acoustic wave was created to temporally excite the flow near the resonance frequency of an unstable eigenmode corresponding to kts = kw. The range of acoustic forcing levels, ε, and roughness heights, Δh, examined resulted in a linear dependence of receptivity coefficients; however, the larger values of the forcing combination εΔh resulted in subsequent nonlinear development of the Tollmien–Schlichting (T–S) wave. This study provides the first experimental evidence of a marked increase in the receptivity coefficient with increasing obliqueness of the surface waviness in excellent agreement with theory. Detuning of the two-dimensional and oblique disturbances was investigated by varying the streamwise wall-roughness wavenumber αw and measuring the T–S response. For the configuration where laminar-to-turbulent breakdown occurred, the breakdown process was found to be dominated by energy at the fundamental and harmonic frequencies, indicative of K-type breakdown.

scholarly journals Two-dimensional and Three-dimensional Assessment of the Upper Airway

2017 ◽  
Vol 35 (1) ◽  
pp. 357-362 ◽  
Author(s):  
Isabella Vilaza ◽  
Pamela Araya-Díaz ◽  
Hernán M Palomino
Keyword(s):  
Three Dimensional ◽  
Upper Airway ◽  
Two Dimensional ◽  
Dimensional Assessment

scholarly journals Quantitative three-dimensional assessment of Madelung deformity

2019 ◽  
Vol 44 (10) ◽  
pp. 1041-1048
Author(s):  
Abbas Peymani ◽  
Johannes G. G. Dobbe ◽  
Geert J. Streekstra ◽  
Henry R. McCarroll ◽  
Simon D. Strackee
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Madelung Deformity ◽  
Radiocarpal Joint ◽  
Dimensional Parameters ◽  
Wrist Anatomy ◽  
Diagnostic Work ◽  
Dimensional Assessment ◽  
Work Up ◽  
Lunate Fossa

In the diagnostic work-up of Madelung deformity conventional radiographic imaging is often used, assessing the three-dimensional deformity in a two-dimensional manner. A three-dimensional approach could expand our understanding of Madelung deformity’s complex wrist anatomy, while removing inter- and intra-rater differences. We measured previous two-dimensional-based and newly developed three-dimensional-based parameters in 18 patients with Madelung deformity (28 wrists) and 35 healthy participants (56 wrists). Madelung deformity wrists have increased levels of ulnar tilt, lunate subsidence, lunate fossa angle, and palmar carpal displacement. The lunate fossa is more concave and irregular, and angles between scaphoid, lunate, and triquetral bones are decreased. These findings validate the underlying principles of current two-dimensional criteria and reveal previously unknown anatomical abnormalities by utilizing novel three-dimensional parameters to quantify the radiocarpal joint.

Surface Roughness Measurement of Nonwovens Using Three-dimensional Profile Data

2006 ◽  
Vol 76 (11) ◽  
pp. 828-834 ◽  
Author(s):  
In Hwan Sul ◽  
Kyung Hwa Hong ◽  
Huensup Shim ◽  
Tae Jin Kang
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Profile Data ◽  
Roughness Measurement ◽  
Surface Roughness Measurement

Reconstructing architectural geometry

1999 ◽  
Vol 3 (1) ◽  
pp. 65-76
Author(s):  
Earl Mark
Keyword(s):  
Programming Language ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Direct Manipulation ◽  
Architectural Geometry ◽  
Cad Systems ◽  
Computer Screen ◽  
Simple Geometry ◽  
The Creation ◽  
Doubly Curved

CAD systems provide convenient tools for the creation of simple geometry by direct manipulation on the computer screen. They work well enough for two-dimensional construction, but are often inadequate for creating doubly-curved three-dimensional surfaces. The solution proposed here is to use the in-built programming language provided in most CAD systems for direct creation of geometry. Developed for didactic purposes, the stunning reconstructions of Gothic vaults suggest a method of working likely to be of great value to the geometrically adventurous architect.

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