Evaluation of an approximate method for incorporating floating docks in harbor wave prediction models

2005 ◽  
Vol 32 (6) ◽  
pp. 1082-1092 ◽  
Author(s):  
Dongcheng Li ◽  
Vijay Panchang ◽  
Zhaoxiang Tang ◽  
Zeki Demirbilek ◽  
Jerry Ramsden
Keyword(s):  
Prediction Models ◽  
Three Dimensional ◽  
Wave Model ◽  
Three Dimensional Model ◽  
Transmission Coefficients ◽  
Mild Slope Equation ◽  
Wide Range ◽  
Floating Objects ◽  
Floating Breakwaters ◽  
D Model

Computer models based on the two-dimensional (2-D) elliptic mild-slope equation are nowadays routinely used in harbor engineering applications. However, structures like floating breakwaters and docks, which are often encountered in the modeling domain, render the problem for locally three-dimensional model and hence are problematic to incorporate in a 2-D model. Tsay and Liu (Applied Ocean Research. 1983. Vol 5(1): 30–37) proposed a highly simplified but approximate approach that does not violate the overall two dimensionality of the problem. The validity of their approach is examined in detail, and it is found that although their approximation provides results with the correct trend, the actual solutions deviate considerably from the theoretical solutions. We have developed correction factors that may be used to produce more reliable results using the framework of Tsay and Liu. Application of the resulting method to a harbor in Alaska shows that docks in the harbor distort the wave field considerably and create a reflective pattern that has the potential to affect navigation safety in some areas. A by-product of this paper consists of plots of transmission coefficients for waves propagating past rectangular and cylindrical floating objects of infinite extent for a wide range of conditions encountered in practice. Such transmission coefficients are at present readily available in the published literature for selected cases only.Key words: wave, model, mild slope, equation, floating breakwater, dock, marina, harbor.

3-D Model of Proton Exchange Membrane Fuel Cells

2000 ◽  
Author(s):  
Tianhong Zhou ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Three Dimensional Model ◽  
Chemical Reaction Kinetics ◽  
Fuel Cell Performance ◽  
D Model

Abstract A comprehensive three-dimensional model for a proton exchanger membrane (PEM) fuel cell is developed to evaluate the effects of various design and operating parameters on fuel cell performance. The geometrical model includes two distinct flow channels separated by the membrane and electrode assembly (MEA). This model is developed by coupling the governing equations for reactant mass transport and chemical reaction kinetics. To facilitate the numerical solution, the full PEM fuel cell was divided into three coupled domains according to the flow characteristics. The 3-D model has been applied to study species transport, heat transfer, and current density distributions within a fuel cell. The predicated polarization behavior is shown to compare well with experimental data from the literature. The modeling results demonstrate good potential for this computational model to be used in operation simulation as well as design optimization.

scholarly journals Inclusion of landslide tsunamis generation into a depth integrated wave model

2010 ◽  
Vol 10 (11) ◽  
pp. 2259-2268 ◽  
Author(s):  
C. Cecioni ◽  
G. Bellotti
Keyword(s):  
Field Equation ◽  
Small Amplitude ◽  
Laboratory Experiments ◽  
Three Dimensional ◽  
Wave Model ◽  
Dispersive Equations ◽  
Far Field ◽  
Mild Slope Equation ◽  
Calculation Results ◽  
Propagation Of Waves

Abstract. A numerical model based on the mild slope equation, suitable to reproduce the propagation of small amplitude tsunamis in the far field, is extended to reproduce the generation and the propagation of waves generated by landslides. The wave generation is modeled through a forcing term included in the field equation, which reproduces the effects of the movement of a submerged landslide on the fluid. The measurements of three dimensional laboratory experiments, which simulate tsunamis generated by landslide sliding along the flank of a conical island, are compared with the theoretical calculation results. The present approach is also compared with the similar method of Tinti et al. (2006) used for the generation of these waves in depth integrated model, and the different behavior when using frequency-dispersive and non-dispersive equations is highlighted.

scholarly journals A cross-validated three-dimensional model of an englacial and subglacial drainage system in a High-Arctic glacier

2020 ◽  
Vol 66 (256) ◽  
pp. 278-290
Author(s):  
Lena U. Hansen ◽  
Jan A. Piotrowski ◽  
Douglas I. Benn ◽  
Heidi Sevestre
Keyword(s):  
Three Dimensional ◽  
Drainage System ◽  
High Arctic ◽  
Water Drainage ◽  
Three Dimensional Model ◽  
Closure Mechanism ◽  
Ground Penetrating ◽  
Arctic Glacier ◽  
D Model ◽  
Englacial Drainage

AbstractRecent speleological surveys of meltwater drainage systems in cold and polythermal glaciers have documented dynamic englacial and in some cases subglacial conduits formed by the ‘cut-and-closure’ mechanism. Investigations of the spatial distribution of such conduits often require a combination of different methods. Here, we studied the englacial drainage system in the cold glacier Longyearbreen, Svalbard by combining speleological exploration of a 478 m long meltwater conduit with a high-resolution ground penetrating radar (GPR) survey with two different centre-frequencies (25 and 100 MHz). The results yielded a 3-D documentation of the present englacial drainage system. The study shows that the overall form of englacial conduits can be detected from velocity−depth converted GPR data, and that the 3-D model can facilitate a method to pinpoint the reflections in a radargram corresponding with the englacial drainage system, although fine detail cannot be resolved. Visible reflections approximately parallel to the mapped englacial water drainage system likely result from sediment incorporated in the ice or from abandoned parts of the englacial drainage system.

Three-Dimensional Catalytic Regeneration Modeling of SiC Diesel Particulate Filters

2005 ◽  
Vol 128 (2) ◽  
pp. 421-433 ◽  
Author(s):  
George Pontikakis ◽  
Anastassios Stamatelos
Keyword(s):  
Three Dimensional ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Three Dimensional Model ◽  
Standard Equipment ◽  
Efficient System ◽  
Diesel Particulate ◽  
Filter Performance ◽  
D Model ◽  
Diesel Filter

Increasingly stringent diesel particulate emissions standards have reestablished international interest in diesel filters, whose first series application dates back to 1985. Modern diesel engine technology, with computerized engine management systems and advanced, common rail injection systems, needs to be fully exploited to support efficient and durable diesel filter systems with catalytic aids, as standard equipment in passenger cars. Efficient system and components’ optimization requires the use of mathematical models of diesel filter performance. The three-dimensional model for the regeneration of the diesel particulate filter presented in this paper has been developed as an engineering tool for the detailed design optimization of SiC diesel filters of modular structure. The 3-D modeling is achieved by interfacing an existing 1-D model to commercial finite element method software for the computation of the 3-D temperature field within the whole filter assembly, including the adhesive of the filter blocks, the insulation mat, and the metal canning. The 3-D model is applied to real-world component optimization studies of diesel filter systems.

scholarly journals BIM, realidad aumentada y técnicas holográficas aplicadas a la construcción = BIM, increased reality and holographic techniques applied to construction

2018 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Jaime Santamarta Martínez ◽  
Javier Mas Domínguez
Keyword(s):  
Augmented Reality ◽  
New Technologies ◽  
Three Dimensional ◽  
Pilot Project ◽  
Information Modeling ◽  
Three Dimensional Model ◽  
Modeling Methodology ◽  
Wide Range ◽  
Building Information ◽  
Nuevas Tecnologías

ResumenLa metodología BIM (Building Information Modelling), ampliamente implantada en el sector de la edificación y de la arquitectura, ha transformado la manera de desarrollar tanto los proyectos como las obras de construcción. Si bien la esencia de esta metodología se basa en la generación de un modelo tridimensional, la visualización de éste a través de dispositivos bidimensionales hace que la experiencia e interacción con el modelo no sea plena. Es por ello que la aparición en el mercado de nuevas tecnologías como la realidad virtual y la realidad aumentada, abren un amplio abanico de posibilidades ligadas al sector de la construcción. En este sentido, en Acciona Ingeniería se ha desarrollado un proyecto piloto en colaboración con Trimble y Microsoft donde a partir de un modelo BIM se ha creado una realidad aumentada basada en hologramas, que permitan recrear una simulación aplicada a la construcciónAbstractThe BIM (Building Information Modeling) methodology, widely implemented in the building and architecture sector, has transformed the way to develop both projects and construction works. Although the essence of this methodology is based on the generation of a three-dimensional model, the visualization of it through two-dimensional devices means that the experience and interaction with the model is not complete. That is why the appearance in the market of new technologies such as virtual reality and augmented reality, open a wide range of possibilities linked to the construction sector. In this sense, Acciona Engineering has developed a pilot project in collaboration with Trimble and Microsoft where, based on a BIM model, an augmented reality based on holograms has been created, allowing to recreate a simulation applied to construction

The Three-Dimensional Model for a Community

2022 ◽  
pp. 521-534
Author(s):  
Gregory B. White ◽  
Natalie Sjelin
Keyword(s):  
Cyber Security ◽  
Action Plan ◽  
Three Dimensional ◽  
Maturity Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Initial Development ◽  
The Creation ◽  
D Model

The community cyber security maturity model (CCSMM) was designed and developed to provide communities with an action plan to build a viable and sustainable cybersecurity program focused on improving their overall cybersecurity capability. Not long after the initial development of the model, it was realized that there are intertwined relationships that needed to be addressed. This drove the creation of the three-dimensional model broadening the scope to include individuals, organizations, communities, states, and the nation. This chapter will provide an overview of the development and importance of the 3-D model and will describe the scope areas that were included.

scholarly journals Digital Documentation and a 3-D Model of Beaufort Castle via RTK GNSS, Terrestrial Laser Scanner and UAS-based Photogrammetry

2021 ◽  
Vol 310 ◽  
pp. 05002
Author(s):  
Yousef Naanouh ◽  
Vasyutinskaya Stanislava
Keyword(s):  
Laser Scanning ◽  
3D Model ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Terrestrial Laser Scanning ◽  
Three Dimensional Model ◽  
South Lebanon ◽  
Aerial Vehicle ◽  
Digital Documentation ◽  
D Model

Three-dimensional digital technology is important in the maintenance and monitoring of archeological sites. This paper focuses on using a combination of terrestrial laser scanning and unmanned aerial vehicle (Phantom 4 pro) photogrammetry to establish a three-dimensional model and associated digital documentation of Beaufort castle (Arnoun, South Lebanon). The overall discrepancy between the two technologies was sufficient for the generation of convergent data. Thus, the terrestrial laser scanning and phantom 4 photogrammetry data were aligned and merged post-conversion into compatible extensions. A three-D dimensional (3D) model, with planar and perpendicular geometries, based on the hybrid datapoint cloud was developed. This study demonstrates the potential of using the integration of terrestrial laser scanning and photogrammetry in 3D digital documentation and spatial analysis of the Lebanese archeological sites.

Analysis of Conjugate Heat Transfer in a Three-Dimensional Microchannel Heat Sink for Cooling of Electronic Components

1999 ◽  
Author(s):  
Andrei G. Fedorov ◽  
Raymond Viskanta
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Conjugate Heat Transfer ◽  
Stokes Equations ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Solid Substrate ◽  
Microchannel Heat Sink ◽  
Three Dimensional Model ◽  
Wide Range

Abstract A three-dimensional model is developed to investigate flow and conjugate heat transfer in the microchannel-based heat sink for electronic packaging applications. The incompressible laminar flow Navier-Stokes equations of motion as well as the energy conservation equations for the fluid and solid are employed as the governing model equations which are numerically solved using the generalized single-equation framework for solving conjugate problems. First, the theoretical model developed is validated by comparing the model predictions of the thermal resistance and the friction coefficient with available experimental data for a wide range of Reynolds numbers. Then, the parametric calculations are performed to investigate the effects of different working fluids, solid substrate materials and channel geometry on conjugate heat transfer in the microchannel heat sink. The bulk and wall temperature and heat flux distributions as well as the average heat transfer characteristics are reported and discussed. Important practical design recommendations are also provided regarding the cooling efficiency of the microchannel heat sink.

scholarly journals A 3-D Model for a Multilayered Body Loaded Normally and Tangentially Against a Rigid Body: Application to Specific Coatings

1998 ◽  
Vol 120 (4) ◽  
pp. 668-676 ◽  
Author(s):  
S. Plumet ◽  
M.-C. Dubourg
Keyword(s):  
Rigid Body ◽  
Three Dimensional ◽  
Integral Transforms ◽  
Internal Stresses ◽  
Three Dimensional Model ◽  
Linear Elasticity Theory ◽  
Contact Conditions ◽  
Multilayered Body ◽  
Potential Failure ◽  
D Model

Coatings are increasingly used to improve the mechanical and tribological behavior of surfaces. It is necessary to develop models to guide the initial choice of coating/substrate combinations that can withstand the applied loads. A three-dimensional model of an elastic multilayered body, loaded both normally and tangentially against an elliptical rigid body (partial sliding, rolling/sliding conditions), is presented here. This model is based on linear elasticity theory, integral transforms, Fast Fourier Transform, and unilateral contact analysis with friction. Normal and tangential contact conditions between the two bodies are first determined and then used to calculate the multilayered body stress field. One application is given here: The influence of the mechanical properties of coating and substrate, as well as coating thickness, is studied on contact conditions, internal stresses, and potential failure mechanisms.

Comparison of anatomical shoulder prostheses and the proximal humeri of Chinese people

2007 ◽  
Vol 221 (8) ◽  
pp. 921-927 ◽  
Author(s):  
L Zhang ◽  
B Yuan ◽  
C Wang ◽  
Z Liu
Keyword(s):  
Degenerative Change ◽  
Three Dimensional ◽  
Chinese People ◽  
Three Dimensional Model ◽  
Wide Range ◽  
Computed Tomography Scanning ◽  
Head Height ◽  
Large Bone ◽  
Range Of Variation ◽  
Anatomical Parameters

Reconstruction of normal anatomy is important to a successful proximal humeral arthroplasty, in which the surgeon needs to know multiple measured anatomical parameters during the surgery. Based on three-dimensional computed tomography scanning data, computer models of the proximal humeri of 180 Chinese people were built. They came from 77 males and 103 females; their ages ranged from 19 to 86 years. Anatomical parameters including the curvature diameter of the head, the head height, the inclination, and the retro-version were measured using the software in these three-dimensional proximal humerus models. The methodology was valid and the measured results showed marked variations in all those parameters. On average, the curvature diameter of the head was 44.6 mm, ranging from 36.4 to 55.5 mm. The head height was located at 16.7 ± 1.9 mm (minimum, 12.4 mm; maximum, 22.0 mm). The inclination angle ranged from 122.35° to 147.09° (mean, 132.4 ± 4.7°). The proximal humeral retroversion was found to be extremely variable, ranging from -4.71° to 52.46°, and has a mean of 21.11°. Then these measured results were compared with four commonly used anatomical prostheses. The wide range of variation in the normal values makes it difficult to restore anatomical characteristics individually. Thus, the use of an accurate three-dimensional model to guide surgery preoperatively can improve the outcome of some serious cases, such as gross degenerative change and large-bone-loss surgery.

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