Search results for "Boundary"
showing 10 items of 1626 documents
A second strain gradient elasticity theory with second velocity gradient inertia – Part I: Constitutive equations and quasi-static behavior
2013
Abstract A multi-cell homogenization procedure with four geometrically different groups of cell elements (respectively for the bulk, the boundary surface, the edge lines and the corner points of a body) is envisioned, which is able not only to extract the effective constitutive properties of a material, but also to assess the “surface effects” produced by the boundary surface on the near bulk material. Applied to an unbounded material in combination with the thermodynamics energy balance principles, this procedure leads to an equivalent continuum constitutively characterized by (ordinary, double and triple) generalized stresses and momenta. Also, applying this procedure to a (finite) body s…
Efficient Dense Disparity Map Reconstruction using Sparse Measurements
2018
International audience; In this paper, we propose a new stereo matching algorithm able to reconstruct efficiently a dense disparity maps from few sparse disparity measurements. The algorithm is initialized by sampling the reference image using the Simple Linear Iterative Clustering (SLIC) superpixel method. Then, a sparse disparity map is generated only for the obtained boundary pixels. The reconstruction of the entire disparity map is obtained through the scanline propagation method. Outliers were effectively removed using an adaptive vertical median filter. Experimental results were conducted on the standard and the new Middlebury datasets show that the proposed method produces high-quali…
Implementation and application of the actuator line model by OpenFOAM for a vertical axis wind turbine
2017
University of Stavanger has started The Smart Sustainable Campus & Energy Lab project, to gain knowledge and facilitate project based education in the field of renewable and sustainable energy and increase the research effort in the same area. This project includes the future installation of a vertical axis wind turbine on the campus roof. A newly developed Computational Fluid Dynamics (CFD) model by OpenFOAM have been implemented to study the wind behavior over the building and the turbine performance. The online available wind turbine model case from Bachant, Goude and Wosnik from 2016 is used as the starting point. This is a Reynolds-Averaged Navier-Stokes equations (RANS) case set up th…
Effect of amorphous sequences on the longitudinal acoustic modes in partially crystalline polymers. I. Transfer matrix method
1983
A novel theoretical scheme is developed which enables the determination of the LAM-like vibrations of polymer chains made up of crystalline and amorphous parts as they occur in partially crystalline structures. The boundary conditions effective at the junction points are formulated in terms of the compliances of the associated amorphous sequences. These compliances can be derived from their eigenfrequencies and eigenvectors in a disconnected state. The treatment uses a matrix formalism which can be extended to include bending and torsional motions in a general state of vibration of the crystalline stem. A first numerical example demonstrates that the LA mode of a crystalline stem can be str…
Interaction features for prediction of perceptual segmentation:Effects of musicianship and experimental task
2016
As music unfolds in time, structure is recognised and understood by listeners, regardless of their level of musical expertise. A number of studies have found spectral and tonal changes to quite successfully model boundaries between structural sections. However, the effects of musical expertise and experimental task on computational modelling of structure are not yet well understood. These issues need to be addressed to better understand how listeners perceive the structure of music and to improve automatic segmentation algorithms. In this study, computational prediction of segmentation by listeners was investigated for six musical stimuli via a real-time task and an annotation (non real-tim…
Analysis of non-uniform torsion in curved incrementally launched bridges
2014
Abstract Incremental launching is a common and convenient methodology to build continuous girder bridges on several piers. Although it has mainly been applied to straight bridges with box sections, today it is also used for construction of horizontally curved bridges with concrete and composite steel–concrete closed or open sections like I-girders. In these cases the contribution of torsion to the stress state becomes of primary importance when the construction stages of these bridges are analysed. Moreover, the presence of thin-walled cross-sections, makes the analysis of non-uniform torsion fundamental when the angle of twist per unit length is not constant or warping is prevented in thos…
Numerical and experimental investigation of a cross-flow water turbine
2016
ABSTRACTA numerical and experimental study was carried out for validation of a previously proposed design criterion for a cross-flow turbine and a new semi-empirical formula linking inlet velocity to inlet pressure. An experimental test stand was designed to conduct a series of experiments and to measure the efficiency of the turbine designed based on the proposed criterion. The experimental efficiency was compared to that from numerical simulations performed using a RANS model with a shear stress transport (SST) turbulence closure. The proposed semi-empirical velocity formula was also validated against the numerical solutions for cross-flow turbines with different geometries and boundary c…
Efficient analysis of waveguide filters by the integral equation technique and the BI-RME method
2003
This paper presents the study of rectangular waveguide filters with rounded corners in the cross-section of the waveguides. These components are suitable for low-cost mass production and can be rigorously analyzed by efficient CAD tools. The analysis approach described in this paper is based on the integral equation technique in conjunction with the boundary integral-resonant mode expansion method. Two representative examples are also reported.
Fast and accurate analysis and design of substrate integrated waveguide (SIW) filters
2007
This paper describes the application of the boundary integral-resonant mode expansion (BI-RME) method to the accurate modelling of substrate integrated waveguides (SIW). The new formulation fully exploits the particular geometry of this class of structures, thus providing a very efficient analysis method to be used within CAD tools of SIW filters. The advantages of this method have been proved with the successful design of two filters operating in the microwave and millimeter-wave bands.
Light-Scattering and -Absorption of Nanoparticles
2012
To understand the optical response of nanoparticles to the incident light, a theoretical description is needed, which is given in this chapter. In a first approximation, these optical properties can be described using a quasi-static model, which assumes a particle-size much smaller than the wavelength of the light. The derivation of the polarizability of a sphere, which describes its optical properties, and further extensions for spheroidal, rod-shaped and coated particles are given in Sect. 2.2.